There is an emerging demand on techniques addressing the problem of efficiently archiving and (temporal) querying different versions of evolving semantic Web data. While systems archiving and/or temporal querying are still in their early days, we consider this a good time to discuss benchmarks for evaluating storage space efficiency for archives, retrieval functionality they serve, and the performance of various retrieval operations. To this end, we provide a blueprint on benchmarking archives of semantic data by defining a concise set of operators that cover the major aspects of querying of and interacting with such archives. Next, we introduce BEAR, which instantiates this blueprint to serve a concrete set of queries on the basis of real-world evolving data. Finally, we perform an empirical evaluation of current archiving techniques that is meant to serve as a first baseline of future developments on querying archives of evolving RDF data. (authors' abstract) / Series: Working Papers on Information Systems, Information Business and Operations

[pt] Os sistemas de recomendação são um tema de pesquisa constante devido a sua grande quantidade de aplicações práticas. Estes sistemas podem ser abordados de diversas maneiras, sendo uma das mais utilizadas a filtragem colaborativa, em que para recomendar um item a um usuário são utilizados dados de comportamento de outros usuários. Porém, nem sempre os algoritmos de filtragem colaborativa atingem níveis de precisão necessários para serem utilizados em aplicações reais. Desta forma este trabalho tem como objetivo avaliar o desempenho da análise probabilística de semântica latente (PLSA) aplicado a sistemas de recomendação. Este modelo identifica grupos de usuários com comportamento semelhante através de atributos latentes, permitindo que o comportamento dos grupos seja utilizado na recomendação. Para verificar a eficácia do método, apresentamos experimentos com o PLSA utilizando os problemas de recomendação de anúncios na web e a recomendação de filmes. Evidenciamos uma melhoria de 18,7% na precisão da recomendação de anúncios na web e 3,7% de melhoria no erro quadrático sobre a Média das Médias para o corpus do Netflix. Além dos experimentos, o algoritmo foi implementado de forma flexível e reutilizável, permitindo adaptação a outros problemas com esforço reduzido. Tal implementação também foi incorporada como um módulo do LearnAds, um framework de recomendação de anúncios na web. / [en] Recommender systems are a constant research topic because of their large number of practical applications. There are many approaches to address these problems, one of the most widely used being collaborative filtering, in which in order to recommend an item to a user, data of other users` behaviors are employed. However, collaborative filtering algorithms do not always reach levels of precision required for the use in real applications. Within this context, the present work aims to evaluate the performance of the probabilistic latent semantic analysis (PLSA) applied to recommender systems. This model identifies groups of users with similar behaviors through latent attributes, allowing the use of these behaviors in the recommendation. To check the effectiveness of the method, there were presented experiments with problems of both web ad recommending and film recommending. An improvement of 18,7% were found in the accuracy of the recommendation of ads on the web and we also found 3.7% of improvement in Root Mean Square Error over the Means of Means baseline system for the Netflix corpus. Apart from the aforementioned experiments, the algorithm was implemented in a flexible and reusable way, allowing its adaptation to other problems with reduced effort. This implementation has also been incorporated as a module of LearnAds, a framework for the recommendation of ads on the web.

[pt] O consumo de conteúdo jornalístico na Web aumenta a cada dia. No entanto, boa parte desse conteúdo ainda é produzido segundo paradigmas da mídia impressa. Paralelamente a isto, a Web Semântica ou Web 3.0, adiciona uma camada de inteligência à Web, onde computadores são capazes de extrair significados dos conteúdos acessados na Web, e consequentemente, processá-los. Neste trabalho foi definido e testado um modelo de publicação de conteúdo jornalístico apoiado pela Web Semântica. Foi desenvolvida uma ferramenta de apoio para produtores de conteúdo, com o objetivo de melhorar o processo de construção de narrativas jornalísticas para web, através da sugestão de padrões narrativos e de informações objetivas que dão suporte ao tipo de narrativa desejado. Um estudo de caso foi realizado para avaliar em ambiente real o modelo proposto. Um grupo de jornalistas usou a ferramenta desenvolvida, com aceitação unânime. / [en] The use of journalistic content on the web increases every day. However, much of the content is still produced according to the paradigms of print media. Parallel to this, the Semantic Web or Web 3.0, adds a layer of intelligence to the Web, where computers are able to extract meaning from the visited web content, and consequently, process them. This work defined and tested a model of publishing news content supported by the Semantic Web. It was developed a support tool for content producers, in order to improve the process of construction of news stories for the web, using the suggestion of narrative patterns and objective information that support the desired type of narrative. A case study was conducted to evaluate the proposed model in a real environment. A group of journalists used the developed tool, with unanimous acceptance.

[pt] A Web Semântica permite a divulgação de dados na Internet através de um formato comum com o objetivo de integrar ou combinar bases de dados provenientes de diversas fontes. O Instituto Nacional de Pesquisas da Amazônia - INPA possui várias coleções de dados, principalmente científicos, que podem ser divulgadas e utilizadas na pesquisa e desenvolvimento da Amazônia e para o progresso da ciência. O objetivo deste trabalho é investigar como a utilização das tecnologias da Web Semântica, dentre elas os recursos da ferramenta Rexplorator, pode melhorar o processo de pesquisa, através do processamento da semântica, das coleções de dados biológicos do instituto. A abordagem utilizada é de desenvolver casos de uso junto com os próprios pesquisadores, através de operações simples em cima dos modelos RDFS (Resource Description Framework Schema) das próprias bases. Os casos de uso poderão ser reutilizados por outros pesquisadores, inclusive de domínios de pesquisa diferentes. Neste processo de reutilização é possível que os casos de uso sejam customizados e evoluídos colaborativamente no próprio ambiente em que foram desenvolvidos. Como resultado do processo são geradas aplicações Web que abstraem os modelos RDF (Resource Description Framework) nos quais os dados estão representados tornando possível o acesso às informações por outros pesquisadores que não conhecem esses modelos. Essa facilidade de acesso, além de permitir consultas a bases semânticas por usuários leigos em um dado domínio de pesquisa, também visa permitir que pesquisadores possam realizar consultas transdisciplinares enriquecendo sua visão no desenvolvimento da pesquisa, bem como seu poder nas tomadas de decisões políticas, econômicas e sociais, e, consequentemente, uma melhor gestão do conhecimento. / [en] The Semantic Web enables the dissemination of data on the Internet through a common format in order to integrate or combine databases from different sources. The National Institute for Amazonian Research (INPA) has several collections of data, mainly scientific, that can be disclosed and used in the research and development of the Amazon as well as for the advancement of science. The objective of this study is to investigate how the use of Semantic Web technologies, among them the tool Rexplorator, can improve the research process by processing the semantics in collections of biological data. Use cases are developed with input from INPA researchers. Queries are constructed based on RDFS (Resource Description Framework Schema) created for INPAs existing collections. Use cases can be reused by other researchers, including researchers from different fields. In this process of reuse, the customization and collaborative development of use cases is possible. The result of this process is the generation of Web applications that abstract the RDF model on which data are represented. Consequently, other researchers unfamiliar with the RDF model are also able to access information. In addition to enabling semantic queries in databases by lay users in a given field of research, this ease of access enables researchers to make transdisciplinary queries enriching their vision of research development, as well as their power in political, economic and social decision-making, and hence better knowledge management.

[pt] Normalmente, aplicações semânticas utilizam o conceito de linked data, onde é possível obter dados de diversas fontes e em múltiplos formatos. Desta forma, as aplicações semânticas processam muito mais dados do que as aplicações tradicionais. Uma vez que nem todas as informações são públicas, alguma forma de autenticação será imposta ao usuário. Consultar dados de múltiplas fontes pode requerer muitos pedidos de autenticação, normalmente através de uma combinação de conta de usuário e senha. Tais operações consomem tempo e, considerando-se o tempo extra que uma aplicação semântica leva para processar os dados coletados, pode tornar a experiência frustrante e incômoda para os usuários, devendo ser minimizado, sempre que possível. O propósito desta dissertação é o de analisar e comparar as técnicas de autenticação disponíveis para as aplicações semânticas e propor um protocolo mais rápido e mais seguro para autenticação em aplicações semânticas. / [en] Usually, Linked Data makes Semantic Web Applications query much more information for processing than traditional Web applications. Since not all information is public, some form of authentication may be imposed on the user. Querying data from multiple data sources might require many authentication prompts. Such time consuming operations, added to the extra amount of time a Semantic Web application needs to process the data it collects might be frustrating to the users and should be minimized. The purpose of this thesis is to analyze and compare several Semantic Web authentication techniques available, leading to the proposal of a faster and more secure authentication protocol for Semantic Web Applications.

Le Web des Objets s'inscrit dans divers domaines d'application, tels que la domotique, les entreprises, l'industrie, la médecine, la ville, et l'agriculture. Il se présente comme une couche uniforme placée au-dessus de l'Internet des Objets, afin de surmonter l'hétérogénéité des protocoles présents dans ces réseaux. Une valeur ajoutée des applications Web des Objets est de pouvoir combiner l'accès à divers objets connectés et sources de données externes avec des techniques standards de raisonnement sémantique (RDF-S,OWL). Cela leur permet alors d'interpréter et de manipuler de ces données en tant qu'informations contextuelles. Ces informations contextuelles peuvent être exploitées par ces applications afin d'adapter leurs composants en fonction des changements dans leur environnement. L'adaptation contextuelle est un défi majeur pour le Web des Objets. En effet, les solutions d'adaptation existantes sont soit fortement couplées avec leur domaine d'application (étant donne qu'elles reposent sur des modèles de contexte spécifiques au domaine), soit proposées comme composant logiciels autonomes, difficiles à intégrer dans des architectures Web et orientées sémantique. Cela mène alors à des problèmes d'intégration, de performance et de maintenance. Dans cette thèse, nous proposons une solution d'adaptation contextuelle multi préoccupations pour les applications Web des Objets, répondant à des besoins d'utilisabilité, de flexibilité, de pertinence et de performance. Notre travail se base sur un scenario pour l'agriculture numérique et se place dans le cadre de la plateforme orientée-avatar ASAWoO. Premièrement, nous proposons un Meta modèle générique permettant de concevoir des modèles contextuels standards, interopérables et réutilisables. Deuxièmement, nous présentons un cycle de vie du contexte et un workflow d'adaptation contextuelle, permettant la sémantisation de données brutes, ainsi que la contextualisation en parallèle durant l'exécution de l'application. Ce workflow combine des données issues de sources hétérogènes, telles que l'expertise du domaine, les documentations techniques des objets, les données de capteurs et de services Web, etc. Troisièmement, nous présentons une méthode de génération de règles d'adaptations basées sur des situations contextuelles, permettant de limiter l'effort des experts et concepteurs lors de l'élaboration d'applications adaptatives. Quatrièmement, nous proposons deux optimisations pour le raisonnement contextuel : la première adapte la localisation des taches de raisonnement en fonction du contexte, la seconde améliore le processus de maintenance incrémentale d'informations contextuelles / The Web of Things (WoT) takes place in a variety of application domains (e.g. homes, enterprises, industry, healthcare, city, agriculture...). It builds a Web-based uniform layer on top of the Internet of Things (IoT) to overcome the heterogeneity of protocols present in the IoT networks. WoT applications provide added value by combining access to connected objects and external data sources, as well as standard-based reasoning (RDF-S, OWL 2) to allow for interpretation and manipulation of gathered data as contextual information. Contextual information is then exploited to allow these applications to adapt their components to changes in their environment. Yet, contextual adaptation is a major challenge for theWoT. Existing adaptation solutions are either tightly coupled with their application domains (as they rely on domain-specific context models) or offered as standalone software components that hardly fit inWeb-based and semantic architectures. This leads to integration, performance and maintainability problems. In this thesis, we propose a multi-purpose contextual adaptation solution for WoT applications that addresses usability, flexibility, relevance, and performance issues in such applications. Our work is based on a smart agriculture scenario running inside the avatar-based platformASAWoO. First,we provide a generic context meta-model to build standard, interoperable et reusable context models. Second, we present a context lifecycle and a contextual adaptation workflow that provide parallel raw data semantization and contextualization at runtime, using heterogeneous sources (expert knowledge, device documentation, sensors,Web services, etc.). Third, we present a situation-driven adaptation rule design and generation at design time that eases experts and WoT application designers’ work. Fourth, we provide two optimizations of contextual reasoning for theWeb: the first adapts the location of reasoning tasks depending on the context, and the second improves incremental maintenance of contextual information

De nombreux efforts ont été faits ces dernières années pour faciliter la gestion et la représentation des entités culturelles. Toutefois, il existe encore un grand nombre de systèmes souvent isolés et encore utilisés dans les institutions culturelles reposant sur des modèles non sémantiques qui rendent difficile la validation et l’enrichissement des données. Cette thèse a pour but de proposer de nouvelles solutions pour améliorer la représentation et l’enrichissement sémantique de données culturelles en utilisant les principes du Web Sémantique. Pour ce faire, la recherche est focalisée d’une part sur l’adoption de modèles plus sémantiques comme selon les principes de FRBR qui permet de représenter des familles bibliographiques complexes en utilisant un modèle entités associations avec différents niveaux d’abstraction. Toutefois, la qualité d’une telle transformation est cruciale et c’est pourquoi des améliorations doivent être faites au niveau de la configuration et de l’évaluation d’un tel processus. En parallèle, la thèse cherche à profiter de ces nouveaux modèles sémantiques pour faciliter l’interconnexion des données avec des sources externes comme celles du Linked Open Data ou des sources moins structurées (Sites Web, Flux). Cela doit permettre de générer des bases de connaissances thématiques plus en accord avec les besoins des utilisateurs. Cependant, l’agrégation d’informations depuis des sources hétérogènes implique des étapes d’alignement à la fois au niveau du schéma et au niveau des entités / Many efforts have been done these last two decades to facilitate the management and representation of cultural heritage data. However, many systems used in cultural institutions are still based on flat models and are generally isolated which prevents any reuse or validation of information. This Ph.D. aims at proposing new solutions for enhancing the representation and enrichment of cultural entities using the Semantic Web technologies. This work consists in two major steps to reach this objective. On the one hand, the research is focused on the metadata migration process to transform the schema of existing knowledge catalogs to new semantic models. This study is based on a real-world case study using the concepts from the Functional Requirements for Bibliographic Records (FRBR) which allows to generate graph-based knowledge bases. Yet, the quality of such a migration is the cornerstone for a successful adoption. Thus, several challenges related to the tuning and the evaluation of such a process must be faced. On the other hand, the research aims at taking advantage of these semantic models to facilitate the linkage of information with external and structured sources (e.g., Linked Open Data) and extracting additional information from other sources (e.g., microblogging) to build a new generation of thematic knowledge bases according to the user needs. However, in this case, the aggregation of information from heterogeneous sources requires additional steps to match and merge both correspondences at schema and instance level

In this thesis, a framework for improving model-driven system design productivity with Requirements-Driven Design Automation (RDDA) is presented. The key to the proposed approach is to close the semantic gap between requirements, components and architecture by using compatible semantic models for describing product requirements and component capabilities, including constraints. An ontology-based representation language is designed that spans requirements for the application domain, the software design domain and the component domain. Design automation is supported for architecture development by machine-based mapping of desired product/subsystem features and capabilities to library components and by synthesis and maintenance of Systems Modeling Language (SysML) design structure diagrams. The RDDA framework uses standards-based semantic web technologies and can be integrated with exiting modeling tools. Requirements specification is a major component of the system development cycle. Mistakes and omissions in requirements documents lead to ambiguous or wrong interpretation by engineers, causing errors that trickle down in design and implementation with consequences on the overall development cost. We describe a methodology for requirements specification that aims to alleviate the above issues and that produces models for functional requirements that can be automatically validated for completeness and consistency. The RDDA framework uses an ontology-based language for semantic description of functional product requirements, SysML structure diagrams, component constraints, and Quality of Service. The front-end method for requirements specification is the SysML editor in Rhapsody. A requirements model in Web Ontology Language (OWL) is converted from SysML to Extensible Markup Language Metadata Interchange (XMI) representation. / The specification is validated for completeness and consistency with a ruled-based system implemented in Prolog. With our methodology, omission s and several types of consistency errors present in the requirements specification are detected early on, before the design stage. Component selection and design automation have the potential to play a major role in reducing the system development time and cost caused by the rapid change in technology advances and the large solution search space. In our work, we start from a structured representation of requirements and components using SysML, and based on specific set of rules written in Prolog, we partially automate the process of architecture design. / by Mihai Fonoage. / Thesis (Ph.D.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.

Esta tese propõe um modelo de navegação exploratória para a infra-estrutura da Web Semântica, denominado Navigation and Exploration Model (NAVE). O modelo NAVE foi desenvolvido com base na literatura de information searching, nos níveis de atividades de information seeking, e na estratégia de orienteering. O objetivo é facilitar o projeto e desenvolvimento de sistemas de navegação exploratória. O NAVE é descrito por meio de uma representação gráfica dos estágios e decisões do processo de navegação e suas respectivas técnicas de suporte à navegação, além de recomendações. Um sistema, denominado de Exploratory Navigation System (ENS), foi desenvolvido para avaliar a viabilidade de utilizar o modelo NAVE em aplicações reais. O sistema ENS é composto de diversas ferramentas de navegação que permitem ao usuário escolher a ferramenta adequada, ou a melhor combinação de ferramentas, provavelmente ajustada ao seu nível de habilidade e conhecimento, à sua preferência, e ao tipo de informação que ele está procurando no momento. O sistema permite ao usuário priorizar de maneiras diferentes as suas escolhas de ferramentas em cada passo de uma estratégia de orienteering, subjacente ao modelo NAVE. Essas ferramentas podem apresentar vantagens complementares no contexto de uma tarefa de information searching. O sistema ENS foi avaliado utilizando uma abordagem tanto qualitativa quanto quantitativa, que serviram para refinar as questões de pesquisa e explorar o modelo NAVE. Primeiro, um estudo de usabilidade foi conduzido que combinou vários métodos, como questionários, think-aloud, entrevistas, e registro da interação do usuário. Esse estudo forneceu informações com relação às ferramentas e o modelo NAVE subjacente, as quais foram consideradas no seu desenvolvimento. Segundo, um estudo experimental foi conduzido para comparar o ENS com uma abordagem de busca por palavra-chave. Os resultados forneceram indicações estatísticas de que os participantes tiveram desempenho superior utilizando o ENS / A model for exploratory navigation in the Semantic Web infrastructure called NAVE - Navigation and Exploration Model - is proposed. NAVE is based on literature of information searching, levels of information seeking activities, and an orienteering strategy. This model aims in particular at facilitating the design and development of exploratory navigation systems. It is described by a graphical representation of stages and decisions of the search process and their respective navigation support techniques, and recommendations. As a proof of concept and also to evaluate the feasibility of using NAVE in real-life applications, a system called ENS - Exploratory Navigation System - was developed. ENS is composed of a variety of navigation tools, enabling users to choose the appropriate tool or the best combination of tools (that is, the best strategy) in agreement with different levels of users\' ability, background, preferences, and kind of information they are looking for at moment. It enables users to prioritize different ways their choices of tools to use at each step in an orienteering strategy embedded on the model NAVE. These tools may present complementary advantages in an information searching task. ENS was evaluated in both qualitative and quantitative approach which served to refine research questions and explore the model NAVE. First, a usability study was conducted which combined a variety of methods, such as questionnaires, think-aloud, interview, and user log recording. This study provided insights regarding the tools and the underlying model which were considered in its further development. Second, an experimental study was conducted in order to compare the ENS with a keyword search approach. The findings provided statistical indications that participants had a better performance using the ENS

Este trabalho é um estudo exploratório interdisciplinar, pois converge de duas áreas não pertencentes à mesma classe acadêmica, Ciência da Informação (CI) e Ciência da Computação. O objetivo é, além de estudar a representação no ambiente virtual, encontrar uma forma de representar a informação não textual (multimídia) que atenda essas \"novas necessidades\" e possibilidades que a Web Semântica requer no desenvolvimento de contextos com uso do XML. Conforme a complexidade dos documentos multimodais que envolvem textos, vídeos e imagens descritos em mais de um formato, a opção para a interoperabilidade da descrição foi representar o contexto destes documentos com uso de ontologia. Através de uma metodologia de pesquisa qualitativa de análise exploratória e descritiva, apresentam-se ontologias que permitam que esta descrição feita em padrões convencionais, mas interoperáveis, de formatos de descrição, e que possam atingir um conjunto de objetos multimodais. A descrição desta ontologia, em dois formatos interoperáveis, MARC21 e Dublin Core, foi criada utilizando o software Protégé; e para validação da ontologia, foram feitas 3 aplicações práticas com vídeos acadêmicos (uma aula, um trabalho de conclusão de curso e uma defesa de dissertação de mestrado), que possuem imagens retiradas dos slideshows e compostas num documento final. O resultado alcançado é uma representação dinâmica de vídeo, que faça as relações com os outros objetos que a vídeo trás além da interoperabilidade dos formatos de descrição, tais como: Dublin Core e MARC21. / This work is an exploratory interdisciplinary study, since it mixes two different academic areas: Information science (IS) and Computer Science. The search for a new way of represent non-textual information (media) that supplies the current needs and possibilities that semantic web requires on XML developed contexts is one of the aims of this study. According to the complexity of multimodal documents that converge text, videos and images described in more than one format, ontology use was choose to represent the description interoperability. Through a qualitative research using exploratory and descriptive analysis will be presented ontologies that allow the conventional patterns of description to be interoperable, being able to show a multimodal object set. This ontology description was made in two interoperable formats: MARC21 and Dublin Core. It was created using the Protégé software. To validate the ontologies, they will be applied in 3 academic videos (a lesson video, a graduation defense, and a masters defense), and all of three are composed with slideshows images that are attached in the final document. The result obtained is a dynamic video representation that can make relations with the other video objects beyond interoperability of description formats, such as Dublin Core and MARC21.