[pt] Este trabalho aborda problemas de projeto de ontologias tratando-as como teorias e definindo um conjunto de operações que mapeiam ontologias em ontologias, incluindo suas restrições. Inicialmente, o trabalho resume o conhecimento básico necessário para definir a classe de ontologias utilizada e propõe quatro operações para manipular ontologias. Em seguida, mostra o funcionamento destas operações e como elas podem ajudar na criação de novas ontologias. O cerne do trabalho mostra a implementação destas operações em um plug-in do Protégé, detalhando sua arquitetura e incluindo casos de uso. / [en] This work addresses ontology design problems by treating ontologies as theories and by defining a set of operations that map ontologies into ontologies, including their constraints. The work first summarizes the base knowledge needed to define the class of ontologies used and proposes four operations to manipulate them. It then shows how the operations work and how they may help design new ontologies. The core of this work is describing the implementation of the operations over a Protégé plug-in, detailing the architecture and including case-use examples.

Atualmente a popularidade da Web incentiva o desenvolvimento de sistemas hipermídia dedicados ao ensino a distância. Não obstante a maior parte destes sistemas usa os mesmos recursos do ensino tradicional, apresentado o conteúdo como páginas HTML estáticas, não fazendo uso das novas tecnologias que a Web oferece. Um desafío atual é desenvolver sistemas educativos que adaptem seu conteúdo ao estilo de aprendizagem, contexto e nível de conhecimento de cada aluno. Outro assunto de pesquisa é a capacidade de interoperar na Web reutilizando objetos de ensino. Este trabalho apresenta um enfoque que trata esses dois assuntos com as tecnologias da Web Semântica. O trabalho aqui apresentado modela o conhecimento do conteúdo educativo e do perfil do aluno pelo uso de ontologias cujo vocabulário é um refinamento de vocabulários padrões existentes na Web como pontos de referência para apoiar a interoperabilidade semântica. As ontologias permitem a representação numa linguagem formal dos metadados relativos a objetos de ensino simples e das regras que definem suas possíveis formas de agrupamento para desenvolver objetos mais complexos. Estes objetos mais complexos podem ser projetados para se adequar ao perfil de cada aluno por agentes inteligentes que usam a ontologia como origem de suas crenças. A reutilização de objetos de ensino entre diferentes aplicações é viabilizada pela construção de um perfil de aplicação do padrão IEEE LOM-Learning Object Metadata. / Nowadays, the popularity of the Web encourages the development of Hypermedia Systems dedicated to e-learning. Nevertheless, most of the available Web teaching systems apply the traditional paper-based learning resources presented as HTML pages making no use of the new capabilities provided by the Web. There is a challenge to develop educative systems that adapt the educative content to the style of learning, context and background of each student. Another research issue is the capacity to interoperate on the Web reusing learning objects. This work presents an approach to address these two issues by using the technologies of the Semantic Web. The approach presented here models the knowledge of the educative content and the learner’s profile with ontologies whose vocabularies are a refinement of those defined on standards situated on the Web as reference points to provide semantics. Ontologies enable the representation of metadata concerning simple learning objects and the rules that define the way that they can feasibly be assembled to configure more complex ones. These complex learning objects could be created dynamically according to the learners’ profile by intelligent agents that use the ontologies as the source of their beliefs. Interoperability issues were addressed by using an application profile of the IEEE LOM- Learning Object Metadata standard.

Atualmente a popularidade da Web incentiva o desenvolvimento de sistemas hipermídia dedicados ao ensino a distância. Não obstante a maior parte destes sistemas usa os mesmos recursos do ensino tradicional, apresentado o conteúdo como páginas HTML estáticas, não fazendo uso das novas tecnologias que a Web oferece. Um desafío atual é desenvolver sistemas educativos que adaptem seu conteúdo ao estilo de aprendizagem, contexto e nível de conhecimento de cada aluno. Outro assunto de pesquisa é a capacidade de interoperar na Web reutilizando objetos de ensino. Este trabalho apresenta um enfoque que trata esses dois assuntos com as tecnologias da Web Semântica. O trabalho aqui apresentado modela o conhecimento do conteúdo educativo e do perfil do aluno pelo uso de ontologias cujo vocabulário é um refinamento de vocabulários padrões existentes na Web como pontos de referência para apoiar a interoperabilidade semântica. As ontologias permitem a representação numa linguagem formal dos metadados relativos a objetos de ensino simples e das regras que definem suas possíveis formas de agrupamento para desenvolver objetos mais complexos. Estes objetos mais complexos podem ser projetados para se adequar ao perfil de cada aluno por agentes inteligentes que usam a ontologia como origem de suas crenças. A reutilização de objetos de ensino entre diferentes aplicações é viabilizada pela construção de um perfil de aplicação do padrão IEEE LOM-Learning Object Metadata. / Nowadays, the popularity of the Web encourages the development of Hypermedia Systems dedicated to e-learning. Nevertheless, most of the available Web teaching systems apply the traditional paper-based learning resources presented as HTML pages making no use of the new capabilities provided by the Web. There is a challenge to develop educative systems that adapt the educative content to the style of learning, context and background of each student. Another research issue is the capacity to interoperate on the Web reusing learning objects. This work presents an approach to address these two issues by using the technologies of the Semantic Web. The approach presented here models the knowledge of the educative content and the learner’s profile with ontologies whose vocabularies are a refinement of those defined on standards situated on the Web as reference points to provide semantics. Ontologies enable the representation of metadata concerning simple learning objects and the rules that define the way that they can feasibly be assembled to configure more complex ones. These complex learning objects could be created dynamically according to the learners’ profile by intelligent agents that use the ontologies as the source of their beliefs. Interoperability issues were addressed by using an application profile of the IEEE LOM- Learning Object Metadata standard.

Atualmente a popularidade da Web incentiva o desenvolvimento de sistemas hipermídia dedicados ao ensino a distância. Não obstante a maior parte destes sistemas usa os mesmos recursos do ensino tradicional, apresentado o conteúdo como páginas HTML estáticas, não fazendo uso das novas tecnologias que a Web oferece. Um desafío atual é desenvolver sistemas educativos que adaptem seu conteúdo ao estilo de aprendizagem, contexto e nível de conhecimento de cada aluno. Outro assunto de pesquisa é a capacidade de interoperar na Web reutilizando objetos de ensino. Este trabalho apresenta um enfoque que trata esses dois assuntos com as tecnologias da Web Semântica. O trabalho aqui apresentado modela o conhecimento do conteúdo educativo e do perfil do aluno pelo uso de ontologias cujo vocabulário é um refinamento de vocabulários padrões existentes na Web como pontos de referência para apoiar a interoperabilidade semântica. As ontologias permitem a representação numa linguagem formal dos metadados relativos a objetos de ensino simples e das regras que definem suas possíveis formas de agrupamento para desenvolver objetos mais complexos. Estes objetos mais complexos podem ser projetados para se adequar ao perfil de cada aluno por agentes inteligentes que usam a ontologia como origem de suas crenças. A reutilização de objetos de ensino entre diferentes aplicações é viabilizada pela construção de um perfil de aplicação do padrão IEEE LOM-Learning Object Metadata. / Nowadays, the popularity of the Web encourages the development of Hypermedia Systems dedicated to e-learning. Nevertheless, most of the available Web teaching systems apply the traditional paper-based learning resources presented as HTML pages making no use of the new capabilities provided by the Web. There is a challenge to develop educative systems that adapt the educative content to the style of learning, context and background of each student. Another research issue is the capacity to interoperate on the Web reusing learning objects. This work presents an approach to address these two issues by using the technologies of the Semantic Web. The approach presented here models the knowledge of the educative content and the learner’s profile with ontologies whose vocabularies are a refinement of those defined on standards situated on the Web as reference points to provide semantics. Ontologies enable the representation of metadata concerning simple learning objects and the rules that define the way that they can feasibly be assembled to configure more complex ones. These complex learning objects could be created dynamically according to the learners’ profile by intelligent agents that use the ontologies as the source of their beliefs. Interoperability issues were addressed by using an application profile of the IEEE LOM- Learning Object Metadata standard.

The master’s thesis deals with the design of a boiler for RDF combustion, based on the required power output and superheated steam parameters. The first part of the thesis focuses on combustion calculations. Boiler efficiency is also calculated in this chapter, using the heat balance efficiency method. The main part of the thesis consists of dimensional design and heat transfer calculations. The precision of the calculations is checked at the end of the thesis along with the chlorine corrosion, which is considered because of the higher amount of chlorine in the fuel. The thesis comes with a basic schematic of the designed boiler.

Die Vision des Internets als weltumspannendes Informationsnetz ist zur Wirklichkeit geworden. Um die Idee des weltweiten Datennetzes wahr werden zu lassen, wurde das Resource Description Framework RDF entwickelt. Die dieses Netz speisenden Daten sind zu großen Teilen in Datenbanken abgelegt. Eine Abfragesprache für RDF-Daten ist die vom World Wide Web Consortium im Standardisierungsprozess befindliche SPARQL Protocol And Query Language. Die RDF API for PHP ist eine in der Skriptsprache PHP programmierte Funktionsbibliothek zum Arbeiten mit Daten im RDF-Format. Ziel dieser Arbeit ist es, eine effiziente, datenbankgestützte Implementierung von SPARQL auf Basis der RAP-Bibliothek zu schaffen. Nach den Grundlagen des semantischen Netzes werden neben SPARQL und der RDF API for PHP auch konkurrierende Bibliotheken mit SPARQL-Unterstützung vorgestellt. Der bereits existierende, speicherbasierte SPARQL Prozessor des RAP-Frameworks wird analysiert und dessen Probleme identifiziert. Im Folgenden werden die Anforderungen und die Implementierung des neuen datenbankgestützten Prozessors im Detail beschrieben. Abschließend kommt es zur Evaluation der Geschwindigkeit des neuen Prozessors im Vergleich zu anderen SPARQL-fähigen Datensystemen. Während der täglichen Arbeit mit SPARQL hat sich herausgestellt, dass sich das Protokoll aufgrund einiger Unzulänglichkeiten noch nicht vollständig für den praktischen Einsatz eignet. Aus diesem Grund werden abschließend Erweiterungen zu SPARQL vorgestellt, die sich in der Praxis als hilfreich erwiesen haben. Der im Rahmen dieser Diplomarbeit umgesetzte SPARQL Prozessor erweist sich als robust und schnell. Er liegt trotz der Umsetzung mit einer Skriptsprache in der gleichen Leistungsdimension wie andere State-of-the-Art-Implementierungen und ist diesen häufig sogar überlegen. Er wird bereits in mehreren Anwendungen produktiv eingesetzt und ist als Open-Source-Projekt einer internationalen Anwender- und Entwicklergemeinde zugänglich.

Un nombre croissant de sources de données interconnectées sont publiées sur le Web. Cependant, leur schéma peut êtreincomplet ou absent. De plus, les données ne sont pas nécessairement conformes au schéma déclaré. Ce qui rend leur exploitation complexe. Dans cette thèse, nous proposons une approche d’extraction automatique et incrémentale du schéma d’une source à partir de la structure implicite de ses données. Afin decompléter la description des types découverts, nous proposons également une approche de découverte des patterns structurels d’un type. L’approche procède en ligne sans avoir à télécharger ou à parcourir la source. Ce quipeut être coûteux voire impossible car les sources sont interrogées à distance et peuvent imposer des contraintes d’accès, notamment en termes de temps ou de nombre de requêtes. Nous avons abordé le problème de l’annotationafin de trouver pour chaque type un ensemble de labels permettant de rendre compte de sonsens. Nous avons proposé des algorithmes d’annotation qui retrouvent le sens d’un type en utilisant des sources de données de références. Cette approche s’applique aussi bien pour trouver des noms pertinents pour les typesdécouverts que pour enrichir la description des types existants. Enfin, nous nous sommes intéressés à caractériser la conformité entre les données d’une source et le schéma qui les décrit. Nous avons proposé une approche pour l'analyse et l'amélioration de cette conformité et nous avons proposé des facteurs de qualité, les métriques associées, ainsi qu'une extension du schéma permettant de refléter l'hétérogénéité entre les instances d'un type. / An increasing number of linked data sources are published on the Web. However, their schema may be incomplete or missing. In addition, data do not necessarily follow their schema. This flexibility for describing the data eases their evolution, but makes their exploitation more complex. In our work, we have proposed an automatic and incremental approach enabling schema discovery from the implicit structure of the data. To complement the description of the types in a schema, we have also proposed an approach for finding the possible versions (patterns) for each of them. It proceeds online without having to download or browse the source. This can be expensive or even impossible because the sources may have some access limitations, either on the query execution time, or on the number of queries.We have also addressed the problem of annotating the types in a schema, which consists in finding a set of labels capturing their meaning. We have proposed annotation algorithms which provide meaningful labels using external knowledge bases. Our approach can be used to find meaningful type labels during schema discovery, and also to enrichthe description of existing types.Finally, we have proposed an approach to evaluate the gap between a data source and itsschema. To this end, we have proposed a setof quality factors and the associated metrics, aswell as a schema extension allowing to reflect the heterogeneity among instances of the sametype. Both factors and schema extension are used to analyze and improve the conformity between a schema and the instances it describes

Práce se zabývá vizualizací rozdílu mezi dvěma RDF modely. Jsou zde porovnávány existující nástroje a postupy, tyto nástroje jsou rozděleny do dvou kategorií. První kategorie reprezentuje textový přístup k zobrazování ontologií a potažmo jejich rozdílu, druhá zastupuje grafické metody. Na základě jejich zkoumání je navržen nový přístup. Konkrétně se jedná o nástroj, který podporuje paralelní textovou reprezentaci ontologií, která je obohacena o sémantické anotace (delta tags)

[pt] Um ponto importante para o sucesso de sistemas de busca por palavras-chave é um mecanismo de ranqueamento que considera a importância dos documentos recuperados. A noção de importância em grafos é tipicamente computada usando medidas de centralidade, que dependem amplamente do grau dos nós, como o PageRank. Porém, em grafos RDF, a noção de importância não é necessariamente relacionada com o grau do nó. Sendo assim, esta tese aborda dois problemas: (1) como definir uma medida de importância em grafos RDF; (2) como usar essas medidas para ajudar a compilar e ranquear respostas a consultas por palavras-chave sobre grafos RDF. Para resolver estes problemas, esta tese propõe uma nova família de medidas, chamada de InfoRank, e um sistema de busca por palavras-chave, chamado QUIRA, para grafos RDF. Esta tese é concluída com experimentos que mostram que a solução proposta melhora a qualidade dos resultados em benchmarks de busca por palavras-chave. / [en] A key contributor to the success of keyword search systems is a ranking mechanism that considers the importance of the retrieved documents. The notion of importance in graphs is typically computed using centrality measures that highly depend on the degree of the nodes, such as PageRank. However, in RDF graphs, the notion of importance is not necessarily related to the node degree. Therefore, this thesis addresses two problems: (1) how to define importance measures for RDF graphs; (2) how to use these measures to help compile and rank results of keyword queries over RDF graphs. To solve these problems, the thesis proposes a novel family of measures, called InfoRank, and a keyword search system, called QUIRA, for RDF graphs. Finally, this thesis concludes with experiments showing that the proposed solution improves the quality of the results in two keyword search benchmarks.

Ένα υποσύνολο του τεράστιου όγκου πληροφοριών του Ιστού αφορά τα Ανοικτά Δεδομένα (Open Data), τα οποία αποτελούν πληροφορίες, δημόσιες ή άλλες, στις οποίες ο καθένας μπορεί να έχει πρόσβαση και να τις χρησιμοποιεί περαιτέρω για οποιονδήποτε σκοπό με στόχο να προσθέσει αξία σε αυτές. Η δυναμική των ανοιχτών δεδομένων γίνεται αντιληπτή όταν σύνολα δεδομένων των δημόσιων οργανισμών μετατρέπονται σε πραγματικά ανοιχτά δεδομένα, δηλαδή χωρίς νομικούς, οικονομικούς ή τεχνολογικούς περιορισμούς για την περαιτέρω χρήση τους από τρίτους. Τα ανοικτά δεδομένα ενός Τμήματος ή Σχολής Πανεπιστημίου μπορούν να δημιουργήσουν προστιθέμενη αξία και να έχουν θετικό αντίκτυπο σε πολλές διαφορετικές περιοχές, στη συμμετοχή, την καινοτομία, τη βελτίωση της αποδοτικότητας και αποτελεσματικότητας των Πανεπιστημιακών υπηρεσιών, την παραγωγή νέων γνώσεων από συνδυασμό στοιχείων κ.α. Ο τελικός στόχος είναι τα ανοικτά δεδομένα να καταστούν Ανοικτά Διασυνδεδεμένα Δεδομένα. Τα Διασυνδεδεμένα Δεδομένα, αποκτούν νόημα αντιληπτό και επεξεργάσιμο από μηχανές, επειδή περιγράφονται σημασιολογικά με την χρήση οντολογιών. Έτσι τα δεδομένα γίνονται πιο «έξυπνα» και πιο χρήσιμα μέσα από την διάρθρωση που αποκτούν. Στην παρούσα διπλωματική εργασία, υλοποιείται μια πρότυπη δικτυακή πύλη με την χρήση του Συστήματος Διαχείρισης Περιεχομένου CMS Drupal, το οποίο ενσωματώνει τεχνολογίες Σημασιολογικού Ιστού στον πυρήνα του, με σκοπό την μετατροπή των δεδομένων ενός Τμήματος ή Σχολής Πανεπιστημίου σε Ανοικτά Διασυνδεδεμένα Δεδομένα διαθέσιμα στην τρίτη γενιά του Ιστού τον Σημασιολογικό Ιστό. / A subset of the vast amount of information of the web is concerned with open data, which is information, whether public or other, in which everyone can have access and use it for any purpose with a view to add value. The dynamics of open data becomes noticeable when datasets of public bodies are transformed into truly open data , i.e. without legal, financial or technological limitations for further use by third parties. The open data of a university department or faculty can add value and have a positive impact on many different areas such as participation, innovation, improvisation of the efficiency and effectiveness of university services, generating new knowledge from a combination of elements , etc. The ultimate goal is to transform open data into open linked data. The linked data , become meaningful and processable by machines, given that they are semantically described, using ontologies. Thus, the data become more " intelligent " and more useful through the structure they acquire. In this thesis , a prototype web portal is implemented using the content management system CMS Drupal, which incorporates semantic web technologies in the core, in order to convert the data of a University Department or School in open linked data available in the third generation web semantic web.