View-based user interfaces for the Semantic Web

This thesis explores the possibilities of using the view-based search paradigm to create intelligent user interfaces on the Semantic Web. After surveying several semantic search techniques, the view-based search paradigm is explained, and argued to fit in a valuable niche in the field. To test the argument, numerous portals with different user interfaces and data were built using the paradigm. Based on the results of these experiments, this thesis argues that the paradigm provides a strong, extensible and flexible base on which to built semantic user interfaces. Designing the actual systems to be as adaptable as possible is also discussed

Narrative Cartography with Knowledge Graphs

Narrative cartography is a discipline which studies the interwoven nature of stories and maps. However, conventional geovisualization techniques of narratives often encounter several prominent challenges, including the data acquisition & integration challenge and the semantic challenge. To tackle these challenges, in this paper, we propose the idea of narrative cartography with knowledge graphs (KGs). Firstly, to tackle the data acquisition & integration challenge, we develop a set of KG-based GeoEnrichment toolboxes to allow users to search and retrieve relevant data from integrated cross-domain knowledge graphs for narrative mapping from within a GISystem. With the help of this tool, the retrieved data from KGs are directly materialized in a GIS format which is ready for spatial analysis and mapping. Two use cases — Magellan’s expedition and World War II — are presented to show the effectiveness of this approach. In the meantime, several limitations are identified from this approach, such as data incompleteness, semantic incompatibility, and the semantic challenge in geovisualization. For the later two limitations, we propose a modular ontology for narrative cartography, which formalizes both the map content (Map Content Module) and the geovisualization process (Cartography Module). We demonstrate that, by representing both the map content and the geovisualization process in KGs (an ontology), we can realize both data reusability and map reproducibility for narrative cartography

Microtheories for SDI - Accounting for diversity of local conceptualisations at a global level

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.The categorization and conceptualization of geographic features is fundamental to cartography, geographic information retrieval, routing applications, spatial decision support and data sharing in general. However, there is no standard conceptualization of the world. Humans conceptualize features based on numerous factors including cultural background, knowledge, motivation and particularly space and time. Thus, geographic features are prone to multiple, context-dependent conceptualizations reflecting local conditions. This creates semantic heterogeneity and undermines interoperability. Standardization of a shared definition is often employed to overcome semantic heterogeneity. However, this approach loses important local diversity in feature conceptualizations and may result in feature definitions which are too broad or too specific. This work proposes the use of microtheories in Spatial Data Infrastructures, such as INSPIRE, to account for diversity of local conceptualizations while maintaining interoperability at a global level. It introduces a novel method of structuring microtheories based on space and time, represented by administrative boundaries, to reflect variations in feature conceptualization. A bottom-up approach, based on non-standard inference, is used to create an appropriate global-level feature definition from the local definitions. Conceptualizations of rivers, forests and estuaries throughout Europe are used to demonstrate how the approach can improve the INSPIRE data model and ease its adoption by European member states

Analysis and Design of Computational News Angles

A key skill for a journalist is the ability to assess the newsworthiness of an event or situation. To this purpose journalists often rely on news angles, conceptual criteria that are used both i) to assess whether something is newsworthy and also ii) to shape the structure of the resulting news item. As journalism becomes increasingly computer-supported, and more and more sources of potentially newsworthy data become available in real time, it makes sense to try and equip journalistic software tools with operational versions of news angles, so that, when searching this vast data space, these tools can both identify effectively the events most relevant to the target audience, and also link them to appropriate news angles. In this paper we analyse the notion of news angle and, in particular, we i) introduce a formal framework and data schema for representing news angles and related concepts and ii) carry out a preliminary analysis and characterization of a number of commonly used news angles, both in terms of our formal model and also in terms of the computational reasoning capabilities that are needed to apply them effectively to real-world scenarios. This study provides a stepping stone towards our ultimate goal of realizing a solution capable of exploiting a library of news angles to identify potentially newsworthy events in a large journalistic data space

An Ontology for Modeling Cultural Heritage Knowledge in Urban Tourism

Urban tourism information available on Internet has been of enormous relevance to motivate the tourism in many countries. There exist many applications focused on promoting and preserving the cultural heritage, through urban tourism, which in turn demand a well-defined and standard model for representing the whole knowledge of this domain, thus ensuring interoperable and flexible applications. Current studies propose the use of ontologies to formally model such knowledge. Nonetheless, most of them only represent partial knowledge of cultural heritage or are restrictive to an indoor perspective (i.e., museum ontologies). In this context, we propose the ontology CURIOCITY ( Cultural Heritage for Urban Tourism in Indoor/Outdoor environments of the CITY ), to represent the cultural heritage knowledge based on UNESCO’s definitions. CURIOCITY ontology has a three-level architecture (Upper, Middle, and Lower ontologies) in accordance with a purpose of modularity and levels of specificity. In this paper, we describe in detail all modules of CURIOCITY ontology and perform a comparative evaluation with state-of-the-art ontologies. Additionally, to demonstrate the suitability of CURIOCITY ontology, we show several touristic services offered through a framework supported in the ontology. The framework includes an automatic population process, that allows transforming a museum data repository (in CSV format) into RDF triples of CURIOCITY ontology to automatically populate the CURIOCITY repository, and facilities to develop a set of tourism applications and services, following the UNESCO’s definitions

Methods for Building Semantic Portals

Semantic portals are information systems which collect information from several sources and combine them using semantic web technologies into a user interface that solves information needs of users. Creating such portals requires methods and tools from multiple disciplines, including knowledge representation, information retrieval, information extraction, and user interface design. This thesis explores methods for building and improving semantic portals and other semantic web applications with contributions in three areas. The studies included in the thesis draw from the design science methodology in information systems research. First, a method for creating of faceted search user interfaces for semantic portals utilizing controlled vocabularies with a complex hierarchical structure is presented. The results show that the method allows the creation of user-centric search facets that hide the complex hierarchies from the user, resulting in a user-friendly faceted search interface. Second, the creation of structured metadata from text documents is enhanced by adapting a state of the art automatic subject indexing system to Finnish language texts. The results show that using a suitable combination of existing tools, automatic subject indexing quality comparable to that of human indexers can be attained in a highly inflected language such as Finnish. Finally, the quality of controlled vocabularies such as thesauri and lightweight ontologies is examined by developing a set of quality criteria for vocabularies expressed using the SKOS standard, and methods for correcting structural problems in SKOS vocabularies are presented. The results show that most published SKOS vocabularies suffer from quality issues and violate the SKOS integrity conditions. However, the great majority of such problems were corrected by the methods presented in this dissertation. The methods have been implemented in several real world applications, including the HealthFinland health information portal, the ARPA information extraction toolkit, and the ONKI ontology library system.Semanttiset portaalit ovat tietojärjestelmiä, jotka keräävät tietoa useista lähteistä ja yhdistävät ne semanttisen webin teknologioiden avulla käyttäjien tiedontarpeita tukevaksi käyttöliittymäksi. Tällaisten portaalien rakentaminen vaatii menetelmiä ja työkaluja useilta tieteenaloilta, mukaan lukien tietämyksen esittäminen, tiedonhaku, tiedon eristäminen ja käyttöliittymäsuunnittelu. Tässä väitöskirjassa tarkastellaan menetelmiä semanttisten portaalien ja muiden semanttisen webin sovellusten rakentamiseksi. Väitöskirjan tulokset jakaantuvat kolmeen osa-alueeseen. Tutkimuksessa käytetyt menetelmät perustuvat informaatiojärjestelmien tutkimuksessa käytettyihin suunnittelutieteen menetelmiin. Ensiksi väitöskirjassa esitetään menetelmä semanttisten portaalien fasettipohjaisten käyttöliittymien luomiseksi monimutkaisten kontrolloitujen sanastojen pohjalta. Tulokset osoittavat, että menetelmä mahdollistaa sellaisten käyttäjäkeskeisten hakunäkymien luomisen, jotka piilottavat monimutkaiset hierarkiat käyttäjältä ja auttavat siten luomaan käyttäjäystävällisen fasettipohjaisen hakukäyttöliittymän. Toiseksi rakenteisen metatiedon tuottamista tekstidokumenteista parannetaan sovittamalla nykyaikainen automaattisen sisällönkuvailun järjestelmä suomenkieliselle tekstiaineistolle. Tulokset osoittavat, että käyttämällä sopivaa yhdistelmää olemassaolevista työkaluista saavutetaan ihmistyönä tehtyyn sisällönkuvailuun verrattavissa oleva automaattisen sisällönkuvailun laatu myös agglutinatiivisella kielellä kuten suomen kielellä esitetyille aineistoille. Kolmanneksi tarkastellaan kontrolloitujen sanastojen kuten asiasanastojen ja kevytontologioiden laatua kehittämällä laatukriteeristö SKOS-standardin avulla esitetyille sanastoille sekä esittämällä menetelmiä SKOS-sanastojen rakenteisten ongelmien korjaamiseksi. Tulokset osoittavat, että useimmat julkaistut SKOS-sanastot kärsivät laatuongelmista eivätkä noudata SKOS-standardin eheyssääntöjä. Suuri osa näistä ongelmista pystyttiin korjaamaan tässä väitöskirjassa esitetyin menetelmin. Menetelmät on toteutettu useissa käytössä olevissa järjestelmissä, kuten TerveSuomi-terveystietoportaalissa, ARPA-tiedoneristämistyökalussa ja ONKI-ontologiakirjastossa