Semantic Web: – Interoperability,Usability,Applicability

This paper describes the Ontology of units of Measure and related concepts (OM), an OWL ontology of the domain of quantities and units of measure. OM supports making quantitative research data more explicit, so that the data can be integrated, verified and reproduced. The various options for modeling the domain are discussed. For example, physical quantities can be modeled either as classes, instances or properties. The design choices made are based on use cases from our own projects and general experience in the field. The use cases have been implemented as tools and web services. OM is compared with QUDT, another active effort for an OWL model in this domain. We note possibilities for integration of these efforts. We also discuss the role OWL plays in our approach.

We present BibBase, a system for publishing and managing bibliographic data available in BiBTeX files. BibBase uses a powerful yet light-weight approach to transform BiBTeX files into rich Linked Data as well as custom HTML code and RSS feed that can readily be integrated within a user's website while the data can instantly be queried online on the system's SPARQL endpoint. In this paper, we present an overview of several features of our system. We outline several challenges involved in on-the-fly transformation of highly heterogeneous BiBTeX files into high-quality Linked Data, and present our solution to these challenges.

Today's students, being used to constant activity and multitasking in their everyday life, need a high level of social and creative engagement in order to learn; for them, highly interactive learning environments which allow for communication, collaboration, and authoring, are a must. In addition, modern learning theories stress the importance of interactivity and engagement of students for successful learning processes, whereas recent empirical studies provide evidence and confirm this. In this paper, we present how the integration of Social and Semantic Web technologies, often referred to as the Social Semantic Web (SSW), along with the Linked Data paradigm offer potentials for improving the interactivity of today's learning environments, while putting students in control of their learning process spanning across different tools and services. We identify the main principles on which such SSW-supported personal learning environments are based, and illustrate them through the design, implementation, analysis, and evaluation of DEPTHS (DEsign Patterns Teaching Help System) – a SSW-based interactive personal learning environment we have developed for the domain of software design patterns.

The Bologna Process initiated a radical change within higher education institutions. This change triggered the creation of new administrative procedures in the every day life of European universities. It also gave rise to the emergence of new concepts for the description of curricula. It is critical for the successful continuation of this process to support the publication and exchange of information among universities. With this aim in mind, we created the Bowlogna Ontology to model an academic setting as proposed by the Bologna reform. In this paper, we present our efforts to design this ontology and the entire process that lead to its creation starting from the definition of a linguistic lexicon derived from the Bologna reform and its conversion to a formal ontology. We also describe practical applications of our ontology for end-users at universities (such as a faceted search and browsing system for course information).

The Semantic Web, especially in the light of the current focus on its nature as a Web of Data, is a data-centric system, and arguably the largest such system in existence. Data is being created, published, exported, imported, used, transformed and re-used, by different parties and for different purposes. Together, these actions form a lifecycle of data on the Semantic Web. Understanding this lifecycle will help to better understand the nature of data on the SW, to explain paradigm shifts, to compare the functionality of different platforms, to aid the integration of previously disparate implementation efforts or to position various actors on the SW and relate them to each other. However, while conceptualisations of many aspects of the SW exist, no exhaustive data lifecycle has been proposed.

This article proposes a data lifecycle model for the Semantic Web by first looking outward, and performing a survey of lifecycle models in other data-centric domains, such as digital libraries, multimedia, eLearning, knowledge and Web content management or ontology development. For each domain, an extensive list of models is taken from the literature, and then described and analysed in terms of its different phases, actor roles and other characteristics. By contrasting and comparing the existing models, a meta vocabulary of lifecycle models for data-centric systems — the Abstract Data Lifecycle Model, or ADLM — is developed. In particular, a common set of lifecycle phases, lifecycle features and lifecycle roles is established, as well as additional actor features and generic features of data and metadata. This vocabulary now provides a tool to describe each individual model, relate them to each other, determine similarities and overlaps and eventually establish a new such model for the Semantic Web.

In this paper, we present WebProtégé—a lightweight ontology editor and knowledge acquisition tool for the Web. With the wide adoption of Web 2.0 platforms and the gradual adoption of ontologies and Semantic Web technologies in the real world, we need ontology-development tools that are better suited for the novel ways of interacting, constructing and consuming knowledge. Users today take Web-based content creation and online collaboration for granted. WebProtégé integrates these features as part of the ontology development process itself. We tried to lower the entry barrier to ontology development by providing a tool that is accessible from any Web browser, has extensive support for collaboration, and a highly customizable and pluggable user interface that can be adapted to any level of user expertise. The declarative user interface enabled us to create custom knowledge-acquisition forms tailored for domain experts. We built WebProtégé using the existing Protégé infrastructure, which supports collaboration on the back end side, and the Google Web Toolkit for the front end. The generic and extensible infrastructure allowed us to easily deploy WebProtégé in production settings for several projects. We present the main features of WebProtégé and its architecture and describe briefly some of its uses for real-world projects. WebProtégé is free and open source. An online demo is available at http://webprotege.stanford.edu.

Different kinds of controlled natural language (CNL) have been proposed as a front-end for Semantic Web systems, in order to make them more accessible to users with no background in formal notations and methods. This paper investigates whether OWL statements in CNL are indeed easier to understand than in other notations. To this aim, an experiment with 64 participants was conducted that compares a controlled natural language to a classical OWL notation. Concretely, Attempto Controlled English was compared to a simplified version of the Manchester OWL Syntax. For a reliable and tool-independent evaluation of understandability, the experiment is based on a novel evaluation framework making use of simple and intuitive diagrams. The results show that CNL is easier to understand, needs less learning time, and is more accepted by its users.