Using ontologies: understanding the user experience

Drawing on 118 responses to a survey of ontology use, this paper describes the experiences of those who create and use ontologies. Responses to questions about language and tool use illustrate the dominant position of OWL and provide information about the OWL profiles and particular Description Logic features used. The paper suggests that further research is required into the difficulties experienced with OWL constructs, and with modelling in OWL. The survey also reports on the use of ontology visualization software, finding that the importance of visualization to ontology users varies considerably. This is also an area which requires further investigation. The use of ontology patterns is examined, drawing on further input from a follow-up study devoted exclusively to this topic. Evidence suggests that pattern creation and use are frequently informal processes and there is a need for improved tools. A classification of ontology users into four groups is suggested. It is proposed that the categorisation of users and user behaviour should be taken into account when designing ontology tools and methodologies. This should enable rigorous, user-specific use cases

SPETA: Social pervasive e-tourism advisor

Tourism is one of the major sources of income for many countries. Therefore, providing efficient, real-time service for tourists is a crucial competitive asset which needs to be enhanced using major technological advances. The current research has the objective of integrating technological innovation into an information system, in order to build a better user experience for the tourist. The principal strength of the approach is the fusion of context-aware pervasive systems, GIS systems, social networks and semantics. This paper presents the SPETA system, which uses knowledge of the user’s current location, preferences, as well as a history of past locations, in order to provide the type of recommender services that tourists expect from a real tour guide.This work is supported by the Spanish Ministry of Industry, Tourism, and Commerce under the GODO project (FIT-340000-2007-134), under the PIBES project of the Spanish Committee of Education and Science (TEC2006-12365-C02-01) and under the MID-CBR project of the Spanish Committee of Education and Science (TIN2006-15140-C03-02).Publicad

Focused categorization power of ontologies: General framework and study on simple existential concept expressions

When reusing existing ontologies for publishing a dataset in RDF (or developing a new ontology), preference may be given to those providing extensive subcategorization for important classes (denoted as focus classes). The subcategories may consist not only of named classes but also of compound class expressions. We define the notion of focused categorization power of a given ontology, with respect to a focus class and a concept expression language, as the (estimated) weighted count of the categories that can be built from the ontology’s signature, conform to the language, and are subsumed by the focus class. For the sake of tractable initial experiments we then formulate a restricted concept expression language based on existential restrictions, and heuristically map it to syntactic patterns over ontology axioms (so-called FCE patterns). The characteristics of the chosen concept expression language and associated FCE patterns are investigated using three different empirical sources derived from ontology collections: first, the concept expression pattern frequency in class definitions; second, the occurrence of FCE patterns in the Tbox of ontologies; and last, for class expressions generated from the Tbox of ontologies (through the FCE patterns); their ‘meaningfulness’ was assessed by different groups of users, yielding a ‘quality ordering’ of the concept expression patterns. The complementary analyses are then compared and summarized. To allow for further experimentation, a web-based prototype was also implemented, which covers the whole process of ontology reuse from keyword-based ontology search through the FCP computation to the selection of ontologies and their enrichment with new concepts built from compound expressions

Human Reasoning and Description Logics: Applying Psychological Theory to Understand and Improve the Usability of Description Logics

Description Logics (DLs) are now the most commonly used ontology languages, in part because of the development of the Web Ontology Language (OWL) standards. Yet it is accepted that DLs are difficult to comprehend and work with, particularly for ontology users who are not computer scientists. The Manchester OWL Syntax (MOS) was developed to make DLs more accessible, by using English keywords in place of logic symbols or formal language. Nevertheless, DLs continue to present difficulties, even when represented in MOS. There has been some investigation of what features cause difficulties, specifically in the context of understanding how an entailment (i.e. an inference) follows from a justification (i.e. a minimal subset of the ontology that is sufficient for the entailment to hold), as is required when debugging an ontology. However, there has been little attempt to relate these difficulties to how people naturally reason and use language. This dissertation draws on theories of reasoning from cognitive psychology, and also insights from the philosophy of language, to understand the difficulties experienced with DLs and to make suggestions to mitigate those difficulties. The language features investigated were those known to be commonly used, both on the basis of analyses reported in the literature and after a survey of ontology users. Two experimental studies investigated participants’ ability to reason with DL statements. These studies demonstrate that insights from psychology and the philosophy of language can be used both to understand the difficulties experienced and to make proposals to mitigate those difficulties. The studies suggest that people reason using both the manipulation of syntax and the representation of semantics with mental models; both approaches can lead to errors. Particular difficulties were associated with: functional object properties; negated conjunction; the interaction of negation and the existential or universal restrictions; and nested restrictions. Proposals to mitigate these difficulties include the adoption of new language keywords; tool enhancement, e.g. to provide syntactically alternative expressions; and the introduction during training both of De Morgan’s Laws for conjunction and disjunction, and their analogues for existential and universal restrictions. A third study then investigated the effectiveness of the proposed new keywords; finding that these keywords could mitigate some of the difficulties experienced. Apart from the immediate applicability of these results to DLs, the approach taken in this dissertation could be extended widely to computer languages, including languages for interacting with databases and with Linked Data. Additionally, based on the experience of the three studies, the dissertation makes some methodological recommendations which are relevant to a range of human-computer interaction studies

Um modelo para a composição dinâmica de serviços dependentes do contexo

Nos últimos anos os dispositivos móveis têm cada vez mais um papel importante na vida quotidiana dos utilizadores. Inicialmente apenas como dispositivos de comunicação por voz, evoluíram e começaram a oferecer serviços básicos de acesso a conteúdos Web. Ultimamente, tornaram-se para muitos utilizadores um dos principais meios de acesso aos mais diversos tipos de serviços que a Web oferece, entre eles serviços de comunicação, pesquisa, localização, socialização ou comércio electrónico. É ainda possível observar o interesse de grandes organizações das tecnologias de informação na área dos serviços móveis, que auxiliadas por hardware cada vez mais sofisticado começaram a explorar a utilização de informações contextuais em que o utilizador se encontra, por forma a melhorar a experiência móvel do utilizador. Embora seja grande a diversidade dos serviços móveis que é possível encontrar actualmente na Web, haverá sempre situações em que um utilizador pretende um serviço mais ou menos complexo com o objectivo de realizar uma determinada tarefa mais específica ou personalizada e possa até englobar mais que um serviço. Nesta Tese de Doutoramento propõe-se um modelo para a composição dinâmica de serviços em dispositivos móveis sensível à informação contextual do utilizador, suportado por tecnologias Web. Este modelo utiliza um servidor de aplicações que possibilita a execução dos seus diversos componentes e cuja interacção com o cliente é feita através de Web Services. Para a sua validação, desenvolveu-se um protótipo baseado no modelo, que suporta a composição de serviços sensíveis ao contexto do utilizador para ser aplicado num ambiente de um campus universitário, que foi sujeito a um conjunto de testes funcionais.In recent years mobile devices play an increasingly important role in the daily lives of users. Initially only voice communication devices, they have been developed evolved and began offering basic services for access to Web content. Lately, became for many users one of the principal means of access to a wide range of services that the Web offers, like communication services, research, location, socialization, or e-commerce. It is still possible to see the interest of major IT organizations in the area of mobile services, which aided by increasingly sophisticated hardware began exploring the use of user’s contextual information, to improve mobile user experience. While it is great diversity of mobile services that can be found on the Web today, there will be always situations where a user wants a more or less complex service, in order to solve a particular task more specific or personalized and may even include more than one service. This PhD thesis proposes a model for dynamic composition of services on mobile devices sensitive to contextual information of the user, supported by Web technologies Therefore, this model uses an application server that enables the implementation of his various components of this model and whose customer interaction is done via Web Services. For validation, we have developed a prototype based on the model, which supports composition of services sensitive to the context of the user, to be applied in an environment of a university campus, which was subject to a set of functional tests