The Semantic Web and Linked Data movements with the aim of creating, publishing and interconnecting machine readable information have gained traction in the last years. However, the majority of information still is contained in and exchanged using unstructured documents, such as Web pages, text documents, images and videos. This can also not be expected to change, since text, images and videos are the natural way in which humans interact with information. Semantic structuring of content on the other hand provides a wide range of advantages compared to unstructured information. Semantically-enriched documents facilitate information search and retrieval, presentation, integration, reusability, interoperability and personalization. Looking at the life-cycle of semantic content on the Web of Data, we see quite some progress on the backend side in storing structured content or for linking data and schemata. Nevertheless, the currently least developed aspect of the semantic content life-cycle is from our point of view the user-friendly manual and semi-automatic creation of rich semantic content. In this thesis, we propose a semantics-based user interface model, which aims to reduce the complexity of underlying technologies for semantic enrichment of content by Web users. By surveying existing tools and approaches for semantic content authoring, we extracted a set of guidelines for designing efficient and effective semantic authoring user interfaces. We applied these guidelines to devise a semantics-based user interface model called WYSIWYM (What You See Is What You Mean) which enables integrated authoring, visualization and exploration of unstructured and (semi-)structured content. To assess the applicability of our proposed WYSIWYM model, we incorporated the model into four real-world use cases comprising two general and two domain-specific applications. These use cases address four aspects of the WYSIWYM implementation: 1) Its integration into existing user interfaces, 2) Utilizing it for lightweight text analytics to incentivize users, 3) Dealing with crowdsourcing of semi-structured e-learning content, 4) Incorporating it for authoring of semantic medical prescriptions.

This thesis builds a foundation for the philosophy of theWeb by examining the crucial question: What does a Uniform Resource Identifier (URI) mean? Does it have a sense, and can it refer to things? A philosophical and historical introduction to the Web explains the primary purpose of theWeb as a universal information space for naming and accessing information via URIs. A terminology, based on distinctions in philosophy, is employed to define precisely what is meant by information, language, representation, and reference. These terms are then employed to create a foundational ontology and principles ofWeb architecture. From this perspective, the SemanticWeb is then viewed as the application of the principles of Web architecture to knowledge representation. However, the classical philosophical problems of sense and reference that have been the source of debate within the philosophy of language return. Three main positions are inspected: the logicist position, as exemplified by the descriptivist theory of reference and the first-generation SemanticWeb, the direct reference position, as exemplified by Putnamand Kripke’s causal theory of reference and the second-generation Linked Data initiative, and a Wittgensteinian position that views the Semantic Web as yet another public language. After identifying the public language position as the most promising, a solution of using people’s everyday use of search engines as relevance feedback is proposed as a Wittgensteinian way to determine sense of URIs. This solution is then evaluated on a sample of the Semantic Web discovered by via using queries from a hypertext search engine query log. The results are evaluated and the technique of using relevance feedback from hypertext Web searches to determine relevant Semantic Web URIs in response to user queries is shown to considerably improve baseline performance. Future work for the Web that follows from our argument and experiments is detailed, and outlines of a future philosophy of the Web laid out.

The shift towards global networking brings with it many opportunities and challenges. In this paper, we discuss key technologies in achieving global semantic interoperability among heterogeneous information systems, including both traditional and web data sources. In particular, we focus on the importance of this capability and technologies we have designed to overcome ontological heterogeneity, a common type of disparity in financial information systems. Our approach to representing and reasoning with ontological heterogeneities in data sources is an extension of the Context Interchange (COIN) framework, a mediator-based approach for achieving semantic interoperability among heterogeneous sources and receivers. We also analyze the issue of ontological heterogeneity in the context of source-selection, and offer a declarative solution that combines symbolic solvers and mixed integer programming techniques in a constraint logic-programming framework. Finally, we discuss how these techniques can be coupled with emerging Semantic Web related technologies and standards such as Web-Services, DAML+OIL, and RuleML, to offer scalable solutions for global semantic interoperability. We believe that the synergy of database integration and Semantic Web research can make significant contributions to the financial knowledge integration problem, which has implications in financial services, and many other e-business tasks. / Singapore-MIT Alliance (SMA)

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Thesis (Ph. D.)--College of Computing, Georgia Institute of Technology, 2004. Directed by Ling Liu. / Vita. Includes bibliographical references (leaves 147-155).

Η συγκεκριμένη μεταπτυχιακή διπλωματική εργασία ασχολείται με την αλληλεπίδραση δύο παράλληλων διεργασιών στην προσπάθεια αξιοποίησης του Παγκόσμιου Ιστού (Web): (α) τη διεργασία μετεξέλιξης του Παγκόσμιου Ιστού στο σημασιολογικό Παγκόσμιο Ιστό, (β) τη διεργασία βελτίωσης των διαδικασιών διαπέρασης (crawling) και ψαξίματος (searching) στον Παγκόσμιο Ιστό. Στα πρώτα βήματα του Παγκόσμιου Ιστού το σημαντικότερο ίσως πρόβλημα για τους χρήστες που ήθελαν να αναζητήσουν πληροφορίες σε αυτό ήταν η έλλειψη πολλών και χρήσιμων πηγών. Σταδιακά, αλλά με ιδιαίτερα γρήγορους ρυθμούς ο Παγκόσμιος Ιστός μετατράπηκε σε μία από τις μεγαλύτερες πηγές πληροφοριών που χρησιμοποιεί ο άνθρωπος καθώς όλο και περισσότεροι εισάγουν δεδομένα για κάθε είδους δραστηριότητα και θέμα. Το πρόβλημα των χρηστών λοιπόν που αναζητούν πληροφορίες ανάχθηκε στη γρήγορη εξαγωγή των χρήσιμων, από τον τεράστιο όγκο των παρεχόμενων, πληροφοριών. Όροι και τεχνικές όπως Data Mining (Εξόρυξη Δεδομένων), Information Retrieval (Ανάκτηση Πληροφορίας), Knowledge Management (Διαχείριση Γνώσης) επεκτάθηκαν για να καλύψουν και το νεοεμφανιζόμενο μέσο. Επιπλέον, στην προσπάθεια για καλύτερη ποιότητα των παρεχόμενων αποτελεσμάτων στο χρήστη σημαντικό ρόλο διαδραμάτισε η εκμετάλλευση των ιδιαίτερων στοιχείων που μπορούν να εξαχθούν για τα ενδιαφέροντά του, τόσο στο στάδιο της διαπέρασης, όπου συγκεντρώνονται σελίδες συγκεκριμένης θεματολογίας (topic-focused crawling), όσο και στο στάδιο της αναζήτησης μέσα από αυτές των πιο σημαντικών για τον εκάστοτε χρήστη (personalization). Παράλληλα, καθώς ο Παγκόσμιος Ιστός σταδιακά μετεξελίσσεται στο Σημασιολογικό Παγκόσμιο Ιστό (Semantic Web) νέα μοντέλα και πρότυπα (XML, RDF, OWL) αναπτύσσονται για την προώθηση αυτής της διαδικασίας. Η έκφραση, μετάδοση και αναζήτηση πληροφοριών με χρήση αυτών των προτύπων ανοίγει νέους ορίζοντες στη χρήση του Διαδικτύου. Το βασικό αντικείμενο της εργασίας αυτής είναι η αξιοποίηση των παρεχόμενων μοντέλων και προτύπων του Σημασιολογικού Ιστού σε συνδυασμό με ήδη εφαρμοσμένες ιδέες και αλγορίθμους στον απλό Παγκόσμιο Ιστό ώστε να είναι εφικτή η ταχύτερη και ακριβέστερη ανάκτηση και επεξεργασία πληροφοριών. Δόθηκε επίσης προσπάθεια στην αξιοποίηση τεχνικών που εκμεταλλεύονται τις ιδιαίτερες προτιμήσεις κάθε χρήστη, και στη διερεύνηση της χρήσης των νέων μοντέλων και προτύπων του Σημασιολογικού Ιστού για την προώθηση της διαδικασίας αυτής. / The presented master thesis examines the interaction between two parallel tasks aiming to the better utilization of the World Wide Web: (a) the task of transforming the World Wide Web into Semantic Web, (b) the task of improving the results of crawling and searching methods on the Web. In the advent of the World Wide Web the most disconcerting problem for the users searching for information in the Web was the lack of useful and sufficient sources of information. Gradually, though in really fast pace, the World Wide Web transformed into the biggest storage of information that humans can use. More and more people contribute new data on the web about every aspect of their life, activity, job or interest. Eventually, users searching for information have to deal with another problem, quite the opposite than the one mentioned above. They need to find the information they are looking for through an enormous amount of data in the minimum amount of time spend in browsing. Terms and techniques such as Data Mining, Information Retrieval, Knowledge Management were extended to be applicable and to the newly presented media. Moreover, on the strive for better quality of the results returned to users, the utilization of user’s special interests that can be extracted played an important role both in the field of crawling, where pages of a certain subject are gathered (topic-focused crawling), and in the field of searching, where pages are valued according to each user’s needs (personalization). At the same time, while the World Wide Web gradually transforms into Semantic Web, new standards and models (XML, RDF, OWL) are evolving in order to launch this inquiry. The storage, presentation, transmission and search of information according to those standards open up new horizons in the utilization of the Web. The principal effort of this master thesis is the utilization of the newly provided models and standards of the Semantic Web in conjunction with already tested, positively evaluated and applicable ideas and algorithms of the World Wide Web, in order to achieve higher speed in retrieval and accuracy of information. Moreover, strong efforts were given in integrating techniques that take into account the special preferences of each user and in the exploration of the benefits that come from the adaptation of these new models of the Semantic Web.

The Semantic Web is the future of the Internet. It is the extension to the Internet in which information will be given well-defined meaning, enabling not only humans but also machines to find, share and combine information more easily. In the Semantic Web documents are not merely pages containing a set of words that form their content. They also encode the meaning and structure of those words. This enables various information retrieval techniques to be performed on the documents in addition to the ones restricted to keywords. The goal of this research is to explore a method for querying the Semantic Web using relational database theory and source transformation techniques. We take as input, documents annotated with XML mark-up and the information tags that we are interested in. We then extract and populate a relational view on the annotated XML documents using these tags and the implicit relations in the XML documents. We evaluate the feasibility of our system by testing on a variety of input and we also explore the kinds of queries that can be made on the extracted relational view. / Thesis (Master, Computing) -- Queen's University, 2007-09-27 10:56:13.513

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As Building Information Modeling (BIM) applications become more sophisticated and used within other knowledge domains, the limitations of existing data exchange and sharing methods become apparent. The integration of BIM and Geographic Information System (GIS) can offer substantial benefits to manage the planning process during the design and construction stages. Currently, building (and geospatial) data are shared between BIM software tools through a common data format, such as Industry Foundation Classes (IFC). Because of the diversity and complexity of domain knowledge across BIM and GIS systems, however, these syntactic approaches are not capable of overcoming semantic heterogeneity. This study uses semantic web technology to ensure the highest level of interoperability between existing BIM and GIS tools. The proposed approach is composed of three main steps; ontology construction, semantic integration through interoperable data formats and standards, and query of heterogeneous information sources. Because no application ontology is available to encompass all IFC classes with different attributes, we first develop an IFC-compliant ontology describing the hierarchy structure of BIM objects. Then, we can translate the building's elements and GIS data into semantic web standard formats. Once the information has been gathered from different sources and transformed into an appropriate semantic web format, the SPARQL query language is used in the last step to retrieve this information from a dataset. The completeness of the methodology is validated through a case study and two use case examples.