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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
501

A Lightweight Framework for Universal Fragment Composition

Henriksson, Jakob 19 December 2008 (has links)
Domain-specific languages (DSLs) are useful tools for coping with complexity in software development. DSLs provide developers with appropriate constructs for specifying and solving the problems they are faced with. While the exact definition of DSLs can vary, they can roughly be divided into two categories: embedded and non-embedded. Embedded DSLs (E-DSLs) are integrated into general-purpose host languages (e.g. Java), while non-embedded DSLs (NE-DSLs) are standalone languages with their own tooling (e.g. compilers or interpreters). NE-DSLs can for example be found on the Semantic Web where they are used for querying or describing shared domain models (ontologies). A common theme with DSLs is naturally their support of focused expressive power. However, in many cases they do not support non–domain-specific component-oriented constructs that can be useful for developers. Such constructs are standard in general-purpose languages (procedures, methods, packages, libraries etc.). While E-DSLs have access to such constructs via their host languages, NE-DSLs do not have this opportunity. Instead, to support such notions, each of these languages have to be extended and their tooling updated accordingly. Such modifications can be costly and must be done individually for each language. A solution method for one language cannot easily be reused for another. There currently exist no appropriate technology for tackling this problem in a general manner. Apart from identifying the need for a general approach to address this issue, we extend existing composition technology to provide a language-inclusive solution. We build upon fragment-based composition techniques and make them applicable to arbitrary (context-free) languages. We call this process for the composition techniques’ universalization. The techniques are called fragment-based since their view of components— reusable software units with interfaces—are pieces of source code that conform to an underlying (context-free) language grammar. The universalization process is grammar-driven: given a base language grammar and a description of the compositional needs wrt. the composition techniques, an adapted grammar is created that corresponds to the specified needs. The result is thus an adapted grammar that forms the foundation for allowing to define and compose the desired fragments. We further build upon this grammar-driven universalization approach to allow developers to define the non–domain-specific component-oriented constructs that are needed for NE-DSLs. Developers are able to define both what those constructs should be, and how they are to be interpreted (via composition). Thus, developers can effectively define language extensions and their semantics. This solution is presented in a framework that can be reused for different languages, even if their notion of ‘components’ differ. To demonstrate the approach and show its applicability, we apply it to two Semantic Web related NE-DSLs that are in need of component-oriented constructs. We introduce modules to the rule-based Web query language Xcerpt and role models to the Web Ontology Language OWL.
502

L'interrogation du web de données garantissant des réponses valides par rapport à des critères donnés / Querying the Web of Data guaranteeing valid answers with respect to given criteria

Nguyen, Thanh Binh 03 December 2018 (has links)
Le terme Linked Open Data (LOD) (ou données ouvertes liées) a été introduit pour la première fois par Tim Berners-Lee en 2006. Depuis, les LOD ont connu une importante évolution. Aujourd’hui,nous pouvons constater les milliers de jeux de données présents sur le Web de données. De ce fait, la communauté de recherche s’est confrontée à un certain nombre de défis concernant la récupération et le traitement de données liées.Dans cette thèse, nous nous intéressons au problème de la qualité des données extraites de diverses sources du LOD et nous proposons un système d’interrogation contextuelle qui garantit la qualité des réponses par rapport à un contexte spécifié par l’utilisateur. Nous définissons un cadre d’expression de contraintes et proposons deux approches : l’une naïve et l’autre de réécriture, permettant de filtrer dynamiquement les réponses valides obtenues à partir des sources éventuellement non-valides, ceci au moment de la requête et non pas en cherchant à les valider dans les sources des données. L’approche naïve exécute le processus de validation en générant et en évaluant des sous-requêtes pour chaque réponse candidate en fonction de chaque contrainte. Alors que l’approche de réécriture utilise les contraintes comme des règles de réécriture pour reformuler la requête en un ensemble de requêtes auxiliaires, de sorte que les réponses à ces requêtes réécrites ne sont pas seulement les réponses de la requête initiale mais aussi des réponses valides par rapport à toutes les contraintes intégrées. La preuve de la correction et de la complétude de notre système de réécriture est présentée après un travail de formalisation de la notion de réponse valide par rapport à un contexte. Ces deux approches ont été évaluées et ont montré la praticabilité de notre système.Ceci est notre principale contribution: nous étendons l’ensemble de systèmes de réécriture déjà connus(Chase, C&BC, PerfectRef, Xrewrite, etc.) avec une nouvelle solution efficace pour ce nouveau défi qu’est le filtrage des résultats en fonction d’un contexte utilisateur. Nous généralisons également les conditions de déclenchement de contraintes par rapport aux solutions existantes, en utilisant la notion de one-way MGU. / The term Linked Open Data (LOD) is proposed the first time by Tim Berners-Lee since 2006.Since then, LOD has evolved impressively with thousands datasets on the Web of Data, which has raised a number of challenges for the research community to retrieve and to process LOD.In this thesis, we focus on the problem of quality of retrieved data from various sources of the LOD and we propose a context-driven querying system that guarantees the quality of answers with respect to the quality context defined by users. We define a fragment of constraints and propose two approaches: the naive and the rewriting, which allows us to filter dynamically valid answers at the query time instead of validating them at the data source level. The naive approach performs the validation process by generating and evaluating sub-queries for each candidate answer w.r.t. each constraint. While the rewriting approach uses constraints as rewriting rules to reformulate query into a set of auxiliary queries such that the answers of rewritten-queries are not only the answers of the query but also valid answers w.r.t. all integrated constraints. The proof of the correction and completeness of our rewriting system is presented after formalizing the notion of a valid answers w.r.t. a context. These two approaches have been evaluated and have shown the feasibility of our system.This is our main contribution: we extend the set of well-known query-rewriting systems (Chase, Chase& backchase, PerfectRef, Xrewrite, etc.) with a new effective solution for the new purpose of filtering query results based on constraints in user context. Moreover, we also enlarge the trigger condition of the constraint compared with other works by using the notion of one-way MGU.
503

A Natural Language Interface for Querying Linked Data

Akrin, Christoffer, Tham, Simon January 2020 (has links)
The thesis introduces a proof of concept idea that could spark great interest from many industries. The idea consists of a remote Natural Language Interface (NLI), for querying Knowledge Bases (KBs). The system applies natural language technology tools provided by the Stanford CoreNLP, and queries KBs with the use of the query language SPARQL. Natural Language Processing (NLP) is used to analyze the semantics of a question written in natural language, and generates relational information about the question. With correctly defined relations, the question can be queried on KBs containing relevant Linked Data. The Linked Data follows the Resource Description Framework (RDF) model by expressing relations in the form of semantic triples: subject-predicate-object. With our NLI, any KB can be understood semantically. By providing correct training data, the AI can learn to understand the semantics of the RDF data stored in the KB. The ability to understand the RDF data allows for the process of extracting relational information from questions about the KB. With the relational information, questions can be translated to SPARQL and be queried on the KB.
504

Ontologien als semantische Zündstufe für die digitale Musikwissenschaft?

Münnich, Stefan 20 December 2019 (has links)
Ontologien spielen eine zentrale Rolle für die formalisierte Repräsentation von Wissen und Informationen sowie für die Infrastruktur des sogenannten semantic web. Trotz früherer Initiativen der Bibliotheken und Gedächtnisinstitutionen hat sich die deutschsprachige Musikwissenschaft insgesamt nur sehr zögerlich dem Thema genähert. Im Rahmen einer Bestandsaufnahme werden neben der Erläuterung grundlegender Konzepte, Herausforderungen und Herangehensweisen bei der Modellierung von Ontologien daher auch vielversprechende Modelle und bereits erprobte Anwendungsbeispiele für eine ‚semantische‘ digitale Musikwissenschaft identifiziert. / Ontologies play a crucial role for the formalised representation of knowledge and information as well as for the infrastructure of the semantic web. Despite early initiatives that were driven by libraries and memory institutions, German musicology as a whole has turned very slowly to the subject. In an overview the author addresses basic concepts, challenges, and approaches for ontology design and identifies models and use cases with promising applications for a ‚semantic‘ digital musicology.
505

Semantic based middleware to support nomadic users in IoT-enabled smart environments / Middleware sémantique supportant les utilisateurs nomades évoluant dans des environnements connectés

Christophe, Benoit 07 September 2015 (has links)
Avec le développement de l’Internet des Objets, la réalisation d’environnements composés de diverses ressources connectées (objets, capteurs, services, données, etc.) devient une réalite tangible. De plus, la place prépondérante que les smartphones prennent dans notre vie (l’utilisateur étant toujours connecté) font que ces espaces dits ‘intelligents’ ouvrent la voie au développement de nouveaux types d’applications; embarquées dans les téléphones d’utilisateurs nomades – passant d’un environnement connecté (la maison) à un autre (la salle de réunion) – et se reconfigurant dynamiquement pour utiliser les ressources de l’environnement connecté dans lequel celles-ci se trouvent. La création de telles applications va cependant de pair avec le design d’outils supportant les utilisateurs en mobilité, en particulier afin de réaliser la sélection la plus efficace possible des ressources de l’environnement dans lequel l’utilisateur se trouve. Tandis qu’une telle sélection requiert la définition de modèles permettant de décrire de façon précise les caractéristiques de ces ressources, elle doit également prendre en compte les profils et préférences utilisateurs.Enfin, l’augmentation du nombre de ressources connectées, potentiellement mobiles, requiert également le développement de processus de sélection qui “passent à l’échelle”. Des avancées dans ce champ de recherche restent encore à faire, notamment à cause d’une connaissance assez floue concernant les acteurs (ainsi que leurs interactions) définissant (i.e., prenant part à) l’éco-système qu’est un “espace intelligent”. En outre, la multiplicité de diverses ressources connectées implique des problèmes d’interopérabilité et de scalabilité qu’il est nécessaire d’adresser. Si le Web Sémantique apporte une réponse à des problèmes d’interopérabilité, il en soulève d’autres liés au passage à l’échelle. Enfin, si des modèles représentant des “espaces intelligents” ont été développé, leur formalisme ne couvre que partiellement toutes les caractéristiques des ressoures connectées. En particulier, ces modèles tendent à omettre les caractéristiques temporelles, spatiales où encore d’appartenance liées à l’éco-système dans lequel se trouvent ces ressources. S’appuyant sur mes recherches conduites au sein des Bell Labs, cette dissertation identifie les interactions entre les différents acteurs de cet éco-système et propose des représentations formelles, basées sur une sémantique, permettant de décrire ces acteurs. Cette dissertation propose également des procédures de recherche, permettant à l’utilisateur (ou ses applications) de trouver des ressources connectées en se basant sur l’analyse de leur description sémantique. En particulier, ces procédures s’appuient sur une architecture distribuée, également décrite dans cette dissertation, afin de permettre un passage à l’échelle. Ces aides à l’utilisateur sont implémentées au travers de briques intergicielles déployées dans différentes pièces d’un bâtiment, permettant de conduire des expérimentations afin de s’assurer de la validité de l’approche employée. / With the growth in Internet of Things, the realization of environments composed of diverse connected resources (devices, sensors, services, data, etc.) becomes a tangible reality. Together with the preponderant place that smartphones take in the daily life of users, these nascent smart spaces pave the way to the development of novel types of applications; carried by the phones of nomadic users and dynamically reconfiguring themselves to make use of such appropriate connected resources. Creating these applications however goes hand-in-hand with the design of tools supporting the nomadic users roaming in these spaces, in particular by enabling the efficient selection of resources. While such a selection calls for the design of theoretically grounded descriptions, it should also consider the profile and preferences of the users. Finally, the rise of (possibly mobile) connected resources calls for designing a scalable process underlying this selection. Progress in the field is however sluggish especially because of the ignorance of the stakeholders (and the interactions between them) composing this eco-system of “IoT-enabled smart environments”. Thus, the multiplicity of diverse connected resources entails interoperability and scalability problems. While the Semantic Web helped in solving the interoperability issue, it however emphasizes the scalability one. Thus, misreading of the ecosystem led to producing models partially covering connected resource characteristics.Revolving from our research works performed over the last 6 years, this dissertation identifies the interactions between the stakeholders of the nascent ecosystem to further propose formal representations. The dissertation further designs a framework providing search capabilities to support the selection of connected resources through a semantic analysis. In particular, the framework relies on a distributed architecture that we design in order to manage scalability issues. The framework is embodied in a VR Gateway further deployed in a set of interconnected smart places and that has been assessed by several experimentations.
506

Grafické uživatelské rozhraní pro porovnávání RDF modelů / Graphical User Interface for Comparing RDF Models

Krčmář, Martin Unknown Date (has links)
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)
507

Genealogická sémantická wiki / Genealogic Semantic Wiki

Brychová, Jana Unknown Date (has links)
This thesis project is about possibilities of storing genealogic data in different formats and based on the results it suggests data format which can be used consequently as a source for the vizualization by semantic web. In the scope of the project there is a genealogic application implemented for KiWi platform. This application enable visualization of designed format using prefuse technology. There are basic and aslo some other usefull information about the basic technologies of the semantic web like RDF, XM, ontology, OWL language stated in the document.
508

Towards Accessible, Usable Knowledge Frameworks in Engineering

Mcpherson, Jeffrey 01 January 2014 (has links) (PDF)
A substantial amount of research has been done in the field of engineering knowledge management, where countless ontologies have been developed for various applications within the engineering community. However, despite the success shown in these research efforts, the techniques have not been adopted by industry. This research aims to uncover the reasons for the slow adoption of engineering knowledge frameworks, namely ontologies, in industry. There are two projects covered in this thesis. The first project is the development of a cross-domain ontology for the Biomesh Project, which spans the fields of mechanical engineering, biology, and anthropology. The biology community is known for its embrace of ontologies and has made their use quite popular with the creation of the Gene Ontology. This ontology spawned the establishment of the Open Biological and Biomedical Ontologies (OBO) Foundry, a consortium which approves and curates ontologies in the biology field. No such consortium exists in the field of engineering. This project demonstrates the usefulness of curated reference ontologies. Ontological knowledge bases in four different domains were imported and integrated together to connect previously disparate information. A case study with data from the Biomesh Project demonstrates cross-domain queries and inferences that were not possible before the creation of this ontology. In the second part of this thesis we investigate the usability of current ontology tools. Protégé, the most popular ontology editing tool, is compared to OntoWiki, a semantic wiki. This comparison is done using proven techniques from the field of Human-computer interaction to uncover usability problems and point out areas where each system excels. A field of 16 subjects completed a set of tasks in each system and gave feedback based on their experience. It is shown that while OntoWiki offers users a satisfying interface, it lacks in some areas that can be easily improved. Protégé provides users with adequate functionality, but it is not intended for a novice user.
509

A Semantic Situation Awareness Framework for Indoor Cyber-Physical Systems

Desai, Pratikkumar 29 May 2013 (has links)
No description available.
510

A Semantics-based Approach to Machine Perception

Henson, Cory Andrew January 2013 (has links)
No description available.

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