Representing Distributed Groups with d g FOAF

Abstract. Managing one’s memberships in different online communities increasingly becomes a cumbersome task. This is due to the increasing number of communities in which users participate and in which they share information with different groups of people like colleagues, sports clubs, groups with specific interests, family, friends, and others. These groups use different platforms to perform their tasks such as collabora-tive creation of documents, sharing of documents and media, conducting polls, and others. Thus, the groups are scattered and distributed over multiple community platforms that each require a distinct user account and management of the group. In this paper, we present dgFOAF, an approach for distributed group management based on the well known Friend-of-a-Friend (FOAF) vocabulary. Our dgFOAF approach is inde-pendent of the concrete community platforms we find today and needs no central server. It allows for defining communities across multiple sys-tems and alleviates the community administration task. Applications of dgFOAF range from access restriction to trust support based on commu-nity membership.

A semantic web model for ad hoc context-aware communities : Application to the Smart Place Scenario

International audienceIn this paper, we propose a model for an open framework that allows mobile users to create and to participate to context-aware virtual communities. The model we propose and implement is a generic data model fully compliant with the semantic web data model RDF. This model is suited to let mobile end-users use, create and customize virtual communities. We combine fundamentals for a decentralized semantic web social network with context-aware virtual communities and services. Smart cities scenarios are typically targeted with this approach. It can be implemented in places like metro stations, museums, squares, cinemas, etc. to provide ad hoc context-aware information services to mobile users

A Pattern-Based Core Ontology for Product Lifecycle Management based on DUL

A major challenge in Product Lifecycle Management (PLM) is the exchange of product data across lifecycle phases, information systems, and parties as data formats, structure and quality can vary vastly. Existing approaches focus only on certain phases of PLM, predominantly design and manufacturing, while the subsequent phases of usage/maintenance and disposal are often ignored. However, especially the usage phase is becoming increasingly important for revenue as customer expectation for services beyond the initial purchase of a product is growing. This paper proposes an ontology CO-PLM based on the foundational ontology DOLCE+DnS Ultralite to provide a formal basis for PLM. In contrast to existing approaches, CO-PLM follows an holistic approach covering all phases of PLM and integrates patterns from existing core ontologies

Ubiquitous Semantic Applications

As Semantic Web technology evolves many open areas emerge, which attract more research focus. In addition to quickly expanding Linked Open Data (LOD) cloud, various embeddable metadata formats (e.g. RDFa, microdata) are becoming more common. Corporations are already using existing Web of Data to create new technologies that were not possible before. Watson by IBM an artificial intelligence computer system capable of answering questions posed in natural language can be a great example. On the other hand, ubiquitous devices that have a large number of sensors and integrated devices are becoming increasingly powerful and fully featured computing platforms in our pockets and homes. For many people smartphones and tablet computers have already replaced traditional computers as their window to the Internet and to the Web. Hence, the management and presentation of information that is useful to a user is a main requirement for today’s smartphones. And it is becoming extremely important to provide access to the emerging Web of Data from the ubiquitous devices. In this thesis we investigate how ubiquitous devices can interact with the Semantic Web. We discovered that there are five different approaches for bringing the Semantic Web to ubiquitous devices. We have outlined and discussed in detail existing challenges in implementing this approaches in section 1.2. We have described a conceptual framework for ubiquitous semantic applications in chapter 4. We distinguish three client approaches for accessing semantic data using ubiquitous devices depending on how much of the semantic data processing is performed on the device itself (thin, hybrid and fat clients). These are discussed in chapter 5 along with the solution to every related challenge. Two provider approaches (fat and hybrid) can be distinguished for exposing data from ubiquitous devices on the Semantic Web. These are discussed in chapter 6 along with the solution to every related challenge. We conclude our work with a discussion on each of the contributions of the thesis and propose future work for each of the discussed approach in chapter 7

Distributed Semantic Social Networks: Architecture, Protocols and Applications

Online social networking has become one of the most popular services on the Web. Especially Facebook with its 845Mio+ monthly active users and 100Mrd+ friendship relations creates a Web inside the Web. Drawing on the metaphor of islands, Facebook is becoming more like a continent. However, users are locked up on this continent with hardly any opportunity to communicate easily with users on other islands and continents or even to relocate trans-continentally. In addition to that, privacy, data ownership and freedom of communication issues are problematically in centralized environments. The idea of distributed social networking enables users to overcome the drawbacks of centralized social networks. The goal of this thesis is to provide an architecture for distributed social networking based on semantic technologies. This architecture consists of semantic artifacts, protocols and services which enable social network applications to work in a distributed environment and with semantic interoperability. Furthermore, this thesis presents applications for distributed semantic social networking and discusses user interfaces, architecture and communication strategies for this application category.Soziale Netzwerke gehören zu den beliebtesten Online Diensten im World Wide Web. Insbesondere Facebook mit seinen mehr als 845 Mio. aktiven Nutzern im Monat und mehr als 100 Mrd. Nutzer- Beziehungen erzeugt ein eigenständiges Web im Web. Den Nutzern dieser Sozialen Netzwerke ist es jedoch schwer möglich mit Nutzern in anderen Sozialen Netzwerken zu kommunizieren oder aber mit ihren Daten in ein anderes Netzwerk zu ziehen. Zusätzlich dazu werden u.a. Privatsphäre, Eigentumsrechte an den eigenen Daten und uneingeschränkte Freiheit in der Kommunikation als problematisch empfunden. Die Idee verteilter Soziale Netzwerke ermöglicht es, diese Probleme zentralisierter Sozialer Netzwerke zu überwinden. Das Ziel dieser Arbeit ist die Darstellung einer Architektur verteilter Soziale Netzwerke welche auf semantischen Technologien basiert. Diese Architektur besteht aus semantischen Artefakten, Protokollen und Diensten und ermöglicht die Kommunikation von Sozialen Anwendungen in einer verteilten Infrastruktur. Darüber hinaus präsentiert diese Arbeit mehrere Applikationen für verteilte semantische Soziale Netzwerke und diskutiert deren Nutzer-Schnittstellen, Architektur und Kommunikationsstrategien.