Ontologies on the semantic web

As an informational technology, the World Wide Web has enjoyed spectacular success. In just ten years it has transformed the way information is produced, stored, and shared in arenas as diverse as shopping, family photo albums, and high-level academic research. The “Semantic Web” was touted by its developers as equally revolutionary but has not yet achieved anything like the Web’s exponential uptake. This 17 000 word survey article explores why this might be so, from a perspective that bridges both philosophy and IT

An Analysis of Service Ontologies

Services are increasingly shaping the world’s economic activity. Service provision and consumption have been profiting from advances in ICT, but the decentralization and heterogeneity of the involved service entities still pose engineering challenges. One of these challenges is to achieve semantic interoperability among these autonomous entities. Semantic web technology aims at addressing this challenge on a large scale, and has matured over the last years. This is evident from the various efforts reported in the literature in which service knowledge is represented in terms of ontologies developed either in individual research projects or in standardization bodies. This paper aims at analyzing the most relevant service ontologies available today for their suitability to cope with the service semantic interoperability challenge. We take the vision of the Internet of Services (IoS) as our motivation to identify the requirements for service ontologies. We adopt a formal approach to ontology design and evaluation in our analysis. We start by defining informal competency questions derived from a motivating scenario, and we identify relevant concepts and properties in service ontologies that match the formal ontological representation of these questions. We analyze the service ontologies with our concepts and questions, so that each ontology is positioned and evaluated according to its utility. The gaps we identify as the result of our analysis provide an indication of open challenges and future work

LIME: Towards a Metadata Module for Ontolex

The OntoLex W3C Community Group has been working for more than a year on realizing a proposal for a standard ontol-ogy lexicon model. As the core-specification of the model is almost com-plete, the group started development of additional modules for specific tasks and use cases. We think that in many usage scenarios (e.g. linguistic enrichment, lo-calization and alignment of ontologies) the discovery and exploitation of linguis-tically grounded datasets may benefit from summarizing information about their linguistic expressivity. While the VoID vocabulary covers the need for general metadata about linked datasets, this more specific information demands a dedicated extension. In this paper, we fill this gap by introducing LIME (Linguistic Metadata), a new vocabulary aiming at completing the OntoLex standard with specifications for linguistic metadata.

A Survey of Volunteered Open Geo-Knowledge Bases in the Semantic Web

Over the past decade, rapid advances in web technologies, coupled with innovative models of spatial data collection and consumption, have generated a robust growth in geo-referenced information, resulting in spatial information overload. Increasing 'geographic intelligence' in traditional text-based information retrieval has become a prominent approach to respond to this issue and to fulfill users' spatial information needs. Numerous efforts in the Semantic Geospatial Web, Volunteered Geographic Information (VGI), and the Linking Open Data initiative have converged in a constellation of open knowledge bases, freely available online. In this article, we survey these open knowledge bases, focusing on their geospatial dimension. Particular attention is devoted to the crucial issue of the quality of geo-knowledge bases, as well as of crowdsourced data. A new knowledge base, the OpenStreetMap Semantic Network, is outlined as our contribution to this area. Research directions in information integration and Geographic Information Retrieval (GIR) are then reviewed, with a critical discussion of their current limitations and future prospects

A Critical Look at the Abstraction Based on Macro-Operators

Abstraction can be an effective technique for dealing with the complexity of planning tasks. This paper is aimed at assessing and identifying in which cases abstraction can actually speed-up the overall search. In fact, it is well known that the impact of abstraction on the time spent to search for a solution of a planning problem can be positive or negative, depending on several factors -including the number of objects defined in the domain, the branching factor, and the plan length. Experimental results highlight the role of such aspects on the overall performance of an algorithm that performs the search at the ground-level only, and compares them with the ones obtained by enforcing abstraction

A model-driven approach to the conceptual modeling of situations : from specification to validation

A modelagem de situações para aplicações sensíveis ao contexto, também chamadas de aplicações sensíveis a situações, é, por um lado, uma tarefa chave para o funcionamento adequado dessas aplicações. Por outro lado, essa também é uma tafera árdua graças à complexidade e à vasta gama de tipos de situações possíveis. Com o intuito de facilitar a representação desses tipos de situações em tempo de projeto, foi criada a Linguagem de Modelagem de Situações (Situation Modeling Language - SML), a qual se baseia parcialmente em ricas teorias ontológicas de modelagem conceitual, além de fornecer uma plataforma de detecção de situação em tempo de execução. Apesar do benefício da existência dessa infraestrutura, a tarefa de definir tipos de situação é ainda não-trivial, podendo carregar problemas que dificilmente são detectados por modeladores via inspeções manuais. Esta dissertação tem o propósito de melhorar e facilitar ainda mais a definição de tipos de situação em SML propondo: (i) uma maior integração da linguagem com as teorias ontológicas de modelagem conceitual pelo uso da linguagem OntoUML, visando aumentar a expressividade dos modelos de situação; e (ii) uma abordagem para validação de tipos de situação usando um método formal, visando garantir que os modelos criados correspondam à intenção do modelador. Tanto a integração quanto a validação são implementadas em uma ferramenta para especificação, verificação e validação de tipos de situação ontologicamente enriquecidos.The modeling of situation types for context-aware applications, also called situationaware applications, is, on the one hand, a key task to the proper functioning of those applications. On the other hand, it is also a hard task given the complexity and the wide range of possible situation types. Aiming at facilitating the representation of those types of situations at design-time, the Situation Modeling Language (SML) was created. This language is based partially on rich ontological theories of conceptual modeling and is accompanied by a platform for situation-detection at runtime. Despite the benefits of the availability of this suitable infrastructure, the definition of situation types, being a non-trivial task, can still pose problems that are hardly detected by modelers by manual model inspection. This thesis aims at improving and facilitating the definition of situation types in SML by proposing: (i) the integration between the language and the ontological theories of conceptual modeling by using the OntoUML language, with the purpose of increasing the expressivity of situation type models; and (ii) an approach for the validation of situation type models using a lightweight formal method, aiming at increasing the correspondence between the created models’ instances and the modeler’s intentions. Both the integration and the validation are implemented in a tool for specification, verification and validation of ontologically-enriched situation types.CAPE

Validation Framework for RDF-based Constraint Languages

In this thesis, a validation framework is introduced that enables to consistently execute RDF-based constraint languages on RDF data and to formulate constraints of any type. The framework reduces the representation of constraints to the absolute minimum, is based on formal logics, consists of a small lightweight vocabulary, and ensures consistency regarding validation results and enables constraint transformations for each constraint type across RDF-based constraint languages

Validation Framework for RDF-based Constraint Languages - PhD Thesis Appendix

This paper serves as appendix for the PhD thesis entitled \u27Validation Framework for RDF-based Constraint Languages\u27, submitted to the Department of Economics and Management at the Karlsruhe Institute of Technology (KIT)

UML for the Semantic Web: Transformation-Based Approaches

The perspective role of UML as a conceptual modelling language for the Semantic Web has become an important research topic. We argue that UML could be a key technology for overcoming the ontology development bottleneck thanks to its wide acceptance and sophisticated tool support. Transformational approaches are a promising way of establishing a connection between UML and web-based ontology languages. We compare some proposals for defining transformations between UML and web ontology languages and discuss the different ways they handle the conceptual differences between these languages. We identify commonalities and differences of the approaches and point out open questions that have not or not satisfyingly been addressed by existing approaches