Το RDF (Resource Description Framework), πρότυπο του W3C, είναι ένα μοντέλο δεδομένων για την αναπαράσταση πληροφορίας στον Παγκόσμιο Ιστό και αποτελεί τη θεμελίωση ενός συνόλου τεχνολογιών για τη μοντελοποίηση κατανεμημένης γνώσης στο Σημαντικό Ιστό. Η παρούσα διπλωματική εργασία περιλαμβάνει τη μελέτη της τεχνολογίας RDF και της σημασιολογικής επέκτασης αυτής, του RDF Schema. Επίσης, στα πλαίσια αυτής της μελέτης έγινε συγκριτική αξιολόγηση των ήδη υπαρχόντων αρχιτεκτονικών για την αποθήκευση και επεξεργασία δεδομένων RDF, εκτιμώντας παράλληλα τη συμπεριφορά τους στην περίπτωση των κατανεμημένων αποθεμάτων. Επιπρόσθετα, αξιολογήθηκαν οι δυνατότητες που προσφέρει σε τέτοιους μηχανισμούς η γλώσσα SPARQL, μια γλώσσα επερωτήσεων για RDF η οποία αποτελεί πρότυπο του W3C. Τέλος, ερευνήθηκαν στο επίπεδο των κατανεμημένων αποθεμάτων δύο πολύ σημαντικά χαρακτηριστικά αυτής της τεχνολογίας, η δυνατότητα συνδυασμού των δεδομένων και της εξαγωγής συμπερασμάτων (inferencing) και η υποστασιοποίηση (reification). Στο τελευταίο στάδιο, και βάσει της παραπάνω αποτύπωσης, πραγματοποιήθηκε η ανάπτυξη μιας εφαρμογής σε γλώσσα Java, η οποία επιτρέπει τη σύνδεση σε ένα ή περισσότερα απομακρυσμένα ή και τοπικά αποθέματα RDF, διαθέτοντας τον απαραίτητο μηχανισμό αποστολής επερωτήσεων (queries) προς αυτά. Η συγκεκριμένη εφαρμογή επιτυγχάνει τον κατάλληλο συνδυασμό των διαθέσιμων κατανεμημένων πληροφοριών και την εξαγωγή συμπερασμών, μια διαδικασία που αποτελεί πρωταρχικό στόχο στο πεδίο του Σημαντικού Ιστού. Για την αξιολόγηση των χαρακτηριστικών της χρησιμοποιήθηκαν απλά παραδείγματα που επιβεβαιώνουν την ορθή λειτουργία της και φανερώνουν το εύρος των δυνατοτήτων της. Άλλωστε, η επεκτασιμότητα και η αξιοπιστία ενός τέτοιου μηχανισμού αποτέλεσαν τη φιλοσοφία πάνω στην οποία στηρίχθηκε η ανάπτυξη του, λαμβάνοντας συγχρόνως υπόψη τα ιδιαίτερα χαρακτηριστικά των κατανεμημένων αποθεμάτων εγγράφων RDF. / RDF (Resource Description Framework), a W3C recommendation, is a data model for representing information in the World Wide Web and constitutes the foundation of many existent technologies for the modeling of distributed knowledge in the Semantic Web. This thesis includes a study of the RDF technology and of its semantic extension, RDF Schema. Also, a comparative evaluation was made among already existing frameworks for the storage and management of RDF data, appreciating their behavior in the case of distributed repositories. Moreover, an evaluation was made for the possibilities that SPARQL offers in such mechanisms, a RDF query language and soon a W3C recommendation. Finally, two very important characteristics of this technology were researched in the field of distributed repositories, the possibility of combination of data and export of conclusions (inferencing) and reification. In the last part, and based on the above imprints, an application was developed in Java, which allows the connection to one or more remote and local RDF repositories, having the necessary mechanism as well for making queries. This application successfully combines distributed knowledge and leads to inferencing, something that is a fundamental objective in the field of Semantic Web. For the evaluation of this application's characteristics, simple examples were used that confirm its proper function and reveal the breadth of its possibilities. Scalability and reliability have been the main goals during this application's development phase, having always in mind that we refer to distributed RDF repositories, which are more complicated and have some special characteristics.

L'inclusion de requête est un problème bien étudié sur plusieurs décennies de recherche. En règle générale, il est défini comme le problème de déterminer si le résultat d'une requête est inclus dans le résultat d'une autre requête pour tout ensemble de données. Elle a des applications importantes dans l'optimisation des requêtes et la vérification de bases de connaissances. L'objectif principal de cette thèse est de fournir des procédures solides et com- plètes pour déterminer l'inclusion des requêtes SPARQL en vertu d'exprimés en axiomes logiques de description. De plus, nous mettons en œuvre ces procédures à l'appui des résultats théoriques par l'expérimentation. À ce jour, test d'inclusion de requête a été effectuée à l'aide de différentes techniques: homomorphisme de graphes, bases de données canoniques, les tech- niques de la théorie des automates et par une réduction au problème de la va- lidité de la logique. Dans cette thèse, nous utilisons la derniere technique pour tester l'inclusion des requêtes SPARQL utilisant une logique expressive appelée μ-calcul. Pour ce faire, les graphes RDF sont codés comme des systèmes de transitions, et les requêtes et les axiomes du schéma sont codés comme des formules de μ-calcul. Ainsi, l'inclusion de requêtes peut être réduit á test de validité de formule logique. L'objectif de cette thèse est d'identifier les divers fragments de SPARQL (et PSPARQL) et les langages de description logique de schéma pour lequelle l'inculsion est décidable. En outre, afin de fournir théoriquement et expériment- alement éprouvées procédures de vérifier l'inclusion de ces fragments décid- ables. Pas durer au moins mais, cette thèse propose un point de repère pour les solveurs d'inclusion. Ce benchmark est utilisé pour tester et comparer l'état actuel des solveurs d'inclusion.

Resource Description Framework (RDF) is a modern graph database model which has a proposed extension called RDF*. However, currently there are no tools available that allow for transitions between RDF and RDF*. In this thesis tools were developed that allow for conversions between these two formats. A conversion tool for transforming RDF’s associated query language SPARQL into SPARQL* was also made. Furthermore, tools for converting between RDF* and another graph database model called Property Graph were developed. Measurements of the memory usage and conversion times for the developed conversion tools were made. Where possible, tests were also performed to control that there was no data loss in the conversions. The results showed varying memory usage and conversion times for the different conversions and that some conversions were very difficult to check for data corruption. Complex testing tools would be required to make sure all conversions are made correctly.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-03-31T22:29:13Z No. of bitstreams: 1 ArthurEmanoelCassioDaSilvaESouza_DISSERT.pdf: 1480067 bytes, checksum: 15c2cf114fae56a6c186a5417cecb57f (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-04-04T19:16:06Z (GMT) No. of bitstreams: 1 ArthurEmanoelCassioDaSilvaESouza_DISSERT.pdf: 1480067 bytes, checksum: 15c2cf114fae56a6c186a5417cecb57f (MD5) / Made available in DSpace on 2016-04-04T19:16:06Z (GMT). No. of bitstreams: 1 ArthurEmanoelCassioDaSilvaESouza_DISSERT.pdf: 1480067 bytes, checksum: 15c2cf114fae56a6c186a5417cecb57f (MD5) Previous issue date: 2015-01-28 / A computa??o em nuvem pode ser definida como um modelo computacional distribu?do atrav?s do qual s?o compartilhados recursos (hardware, armazenamento, plataformas de desenvolvimento e comunica??o) na forma de servi?os pagos e acess?veis com um esfor?o m?nimo de gest?o e intera??o. Um grande benef?cio desse modelo ? possibilitar a utiliza??o de variados provedores (i.e. uma arquitetura multiplataforma) para compor um conjunto de servi?os no intuito de obter uma configura??o ?tima em desempenho e custo. Entretanto, a utiliza??o multiplataforma ? impossibilitada pelo problema de cloud lock-in. O cloud lock-in ? a depend?ncia entre uma aplica??o e uma plataforma de nuvem. Ele ? comumente endere?ado por tr?s estrat?gias: (i) uso de camada intermedi?ria que se interp?e aos consumidores de servi?os de nuvem e o provedor, (ii) uso de interfaces padronizadas para acesso a nuvem, ou ainda (iii) uso de modelos com especifica??es abertas. Este trabalho define uma abordagem para avaliar estas estrat?gias. Tal abordagem foi executada e observou-se que apesar dos avan?os conseguidos por estas estrat?gias, nenhuma delas resolve efetivamente o problema do cloud lock-in. Neste sentido, esse trabalho prop?e o uso de Web Sem?ntica para evitar o cloud lock-in, onde modelos em RDF s?o usados para especificar os recursos de uma nuvem, que s?o gerenciados via consultas SPARQL. Nessa dire??o, esse trabalho: (i) apresenta um modelo avaliativo que quantifica o problema do cloud lock-in, (ii) avalia o cloud lock-in entre tr?s solu??es multi-cloud e tr?s plataformas de nuvem, (iii) prop?e utilizar RDF e SPARQL na ger?ncia de recursos de nuvem, (iv) apresenta o Cloud Query Manager (CQM), um servidor SPARQL que implementa a proposta, e (v) compara tr?s solu??es multi-cloud em rela??o ao CQM quanto ao tempo de resposta e a efetividade na resolu??o do cloud lock-in. / Cloud computing can be defined as a distributed computational model by through resources (hardware, storage, development platforms and communication) are shared, as paid services accessible with minimal management effort and interaction. A great benefit of this model is to enable the use of various providers (e.g a multi-cloud architecture) to compose a set of services in order to obtain an optimal configuration for performance and cost. However, the multi-cloud use is precluded by the problem of cloud lock-in. The cloud lock-in is the dependency between an application and a cloud platform. It is commonly addressed by three strategies: (i) use of intermediate layer that stands to consumers of cloud services and the provider, (ii) use of standardized interfaces to access the cloud, or (iii) use of models with open specifications. This paper outlines an approach to evaluate these strategies. This approach was performed and it was found that despite the advances made by these strategies, none of them actually solves the problem of lock-in cloud. In this sense, this work proposes the use of Semantic Web to avoid cloud lock-in, where RDF models are used to specify the features of a cloud, which are managed by SPARQL queries. In this direction, this work: (i) presents an evaluation model that quantifies the problem of cloud lock-in, (ii) evaluates the cloud lock-in from three multi-cloud solutions and three cloud platforms, (iii) proposes using RDF and SPARQL on management of cloud resources, (iv) presents the cloud Query Manager (CQM), an SPARQL server that implements the proposal, and (v) comparing three multi-cloud solutions in relation to CQM on the response time and the effectiveness in the resolution of cloud lock-in.

This thesis is addressing the issue that we are not able to fully utilize the potential of all the data that the contemporary world around us is constantly producing. The goal of this thesis is to implement a Linked Data driven web application generator that allows lay users to generate web applications from multiple RDF data sources. The application generator automatically analyzes the data sources to help the user with the generation process. Each generated application can be configured and published. The generator contains a list of different types of applications that can be generated depending on the type of input data. This list can be extended and the generator works as a framework which simplifies the process of adding support for new types of applications and new types of data. The generator is also a platform. It allows users to create accounts to manage their published applications and it also features a catalog of published applications and a repository of publicly available data sources that any user can use to generate a new application. The generator is integrated into LinkedPipes Visualization tool. Powered by TCPDF (www.tcpdf.org)

The construction industry is a collaborative environment with the involve-ment of multiple disciplines and activities throughout the Building Lifecycle Stages. The collaboration requires the iterative and coordinated exchange of information for significant improvement of the building design, construction and management. The successful representation of these information re-finements enables the identification of the required level of detail (LOD) for data sharing parameters between the multiple disciplines. Since the last dec-ade, LOD is a promising approach for efficient representation of semantically rich BIM data in different levels. Despite the improvement, there is a lack of efficient implementation in building lifecycle functionalities, because of their fundamental heterogeneity, versatility and adaptability. The proposed approach enables the representation of LOD-sensitive BIM data through the formal definition of ontologies. The paper validates this approach based on the concept of competency questions and their respective SPARQL queries. With the demonstration and validation, the paper provides the conceptual proof for the practical application of the developed approach. The proposed solution can also be easily adaptable and applicable to the present BIM pro-cess since the representation of BIM data in different ontologies (BOT, ifcOWL, etc.) are within reach.:1 Introduction and Background; 2 State-of-art-analysis 2.1 LOD systems 2.2 Information Management 3 Ontology-based LOD representation 3.1 LOD framework 3.2 Exemplary demonstration 4 BIM data management 4.1 LOD sensitive BIM data 4.2 LOD framework to processes 5 Framework validation 6 Conclusion and Future work 7 Acknowledgement 8 References

Semantic Web ist eine der größten aktuellen Herausforderungen in der Informatik. Um Daten einem semantischen Wert zuzuweisen, werden Ontologien benutzt. Ontologien definieren und verwalten Konzepte. Letztere beschreiben Objekte, haben Eigenschaften und was hier bedeutender ist, Relationen zueinander. Diese Konzepte und Relationen werden mit Hilfe einer Spezifikation (OWL zum Beispiel) charakterisiert. Diesen Konzepten werden Instanzen zugeordnet. Das heisst, dass beispielweise mit dem Konzept ”Physiker“ die Instanz ”Albert Einstein“ verbunden wird. Um zu erfahren, was ”Albert Einstein“ mit der Stadt Berlin verbindet, gibt es Anfragesprachen, die bekannteste ist SPARQL. Ohne Vorkenntnisse der Struktur einer Ontologie, ist es nicht möglich, präzise Anfragen zu erstellen. Die einzige Möglichkeit herauszufinden was zwei Instanzen verbindet, ist die Nutzung einer SPARQL-Anfrage mit Platzhaltern, also eine Anfrage auf Instanzebene durchzuführen. Es ist viel Aufwand nötig, um eine Anfrage auf Instanzebene zu lösen ohne vorher zu wissen, wie diese Instanzen miteinander verknüpft sein können. Um eine solche Anfrage lösen zu können, müssen alle Relationen, die die erste Instanz betreffen, verfolgt werden, und von den so erreichten Instanzen diesen Vorgang weiterführen, bis die richtige Instanz gefunden wird. Die Instanzebene, auch A-Box genannt, ist die Ebene der tatsächlichen Elemente. Sie enthält zum Beispiel: ”Berlin ist die Hauptstadt von Deutschland“ . Als erstes muss hierbei ”Berlin“ als Instanz des richtigen Konzept erkannt werden. In diesem Fall müsste also ”Berlin“ als eine Instanz des Konzept ”Stadt“ erkannt werden. Die Rückfü ̈hrung zu einem bestimmten Konzept wird in dieser Arbeit als gelöst betrachtet.

Social network data analysis becomes increasingly important today. In order to improve the integration and reuse of their data, many social networks start to apply RDF to present the data. Accordingly, one common approach for social network data analysis is to employ SPARQL to query RDF data. As the sizes of social networks expand rapidly, queries need to be executed in parallel such as using the MapReduce framework. However, the state-of-the-art translation from SPARQL queries to MapReduce jobs mainly follows a two layer rule, in which SPARQL is first translated to SQL join, is not efficient. In this thesis, we introduce two primitives to enable automatic translation from SPARQL to MapReduce, and to enable efficient execution of the SPARQL queries. We use multiple-join-with-filter to substitute traditional SQL multiple join when feasible, and merge different stages in the MapReduce query workflow. The evaluation on social network benchmarks shows that these two primitives can achieve up to 2x speedup in query running time compared with the original two layer scheme.

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