Philipp Frischmuth

An architecture of a distributed semantic social network

Online social networking has become one of the most popular services on the Web. However, current social networks are like walled gardens in which users do not have full control over their data, are bound to specific usage terms of the social network operator and suffer from a lock-in effect due to the lack of interoperability and standards compliance between social networks. In this paper we propose an architecture for an open, distributed social network, which is built solely on Semantic Web standards and emerging best practices. Our architecture combines vocabularies and protocols such as WebID, FOAF, Semantic Pingback and PubSubHubbub into a coherent distributed semantic social network, which is capable to provide all crucial functionalities known from centralized social networks. We present our reference implementation, which utilizes the OntoWiki application framework and take this framework as the basis for an extensive evaluation. Our results show that a distributed social network is feasible, while it also avoids the limitations of centralized solutions.

Weaving a social data web with semantic Pingback

In this paper we tackle some pressing obstacles of the emerging Linked Data Web, namely the quality, timeliness and coherence of data, which are prerequisites in order to provide direct end user benefits. We present an approach for complementing the Linked Data Web with a social dimension by extending the well-known Pingback mechanism, which is a technological cornerstone of the blogosphere, towards a Semantic Pingback. It is based on the advertising of an RPC service for propagating typed RDF links between Data Web resources. Semantic Pingback is downwards compatible with conventional Pingback implementations, thus allowing to connect and interlink resources on the Social Web with resources on the Data Web. We demonstrate its usefulness by showcasing use cases of the Semantic Pingback implementations in the semantic wiki OntoWiki and the Linked Data interface for database-backed Web applications Triplify.

RDFauthor: employing RDFa for collaborative knowledge engineering

In this paper we present RDFauthor, an approach for authoring information that adheres to the RDF data model. RDFauthor completely hides syntax as well as RDF and ontology data model difficulties from end users and allows to edit information on arbitrary RDFa-annotated web pages. RDFauthor extends RDFa with representations for provenance and update endpoint information. RDFauthor is based on extracting RDF triples from RDFa annotations and transforming the RDFa-annotated HTML view into an editable form by using a set of authoring widgets. As a result, every RDFa-annotated web page can be made easily writeable, even if information originates from different sources.

Weaving a distributed, semantic social network for mobile users

Smartphones, which contain a large number of sensors and integrated devices, are becoming increasingly powerful and fully featured computing platforms in our pockets. For many people they already replace the computer as their window to the Internet, to the Web as well as to social networks. Hence, the management and presentation of information about contacts, social relationships and associated information is one of the main requirements and features of todays smartphones. The problem is currently solved only for centralized proprietary platforms (such as Google mail, contacts & calendar) as well as data-silo-like social networks (e.g. Facebook). Within the Semantic Web initiative standards and best-practices for social, Semantic Web applications such as FOAF emerged. However, there is no comprehensive strategy, how these technologies can be used efficiently in a mobile environment. In this paper we present the architecture as well as the implementation of a mobile Social Semantic Web framework, which weaves a distributed social network based on semantic technologies.

OntoWiki - An authoring, publication and visualization interface for the Data Web

OntoWiki is a front-end application for the Semantic Data Web, which was originally developed to support distributed knowledge engineering scenarios. Due to its extensibility it also serves as a development framework for knowledge intensive applications. On the surface, OntoWiki is a generic user interface for arbitrary RDF knowledge graphs. It supports the navigation through RDF knowledge bases using SPARQL-generated lists, tables and trees (e.g. class trees and taxonomies). All resources are automatically represented as hyperlinks and backlinks are created whenever feasible, thus enabling users to easily traverse entire knowledge graphs. Since all collections of resources displayed in OntoWiki are generated by SPARQL queries, they can be further refined by applying additional filters. In order to explore large datasets, a comprehensive statistical data management and visualization method was integrated. We render an architectural overview and explain the navigation, exploration and vi- sualization features provided for RDF based information and derived statistics. To showcase the versatility of OntoWiki and its various deployments in the Linked Data Web, we describe some large-scale use cases in the domains of enterprise data inte- gration, governmental data publication and digital humanities. This article is the first comprehensive presentation of OntoWiki summarizing the advancements after the initial publication in 2006 (4).

Increasing the financial transparency of European Commission project funding

The Financial Transparency System FTS of the European Commission contains information about grants for European Union projects starting from 2007. It allows users to get an overview on EU funding, including information on beneficiaries as well as the amount and type of expenditure and information on the responsible EU department. The original dataset is freely available on the European Commission website, where users can query the data using an HTML form and download it in CSV and most recently XML format. In this article, we describe the transformation of this data to RDF and its interlinking with other datasets. We show that this allows interesting queries over the data, which were very difficult without this conversion. The main benefit of the dataset is an increased financial transparency of EU project funding. The RDF version of the FTS dataset will become part of the EU Open Data Portal and eventually be hosted and maintained by the European Union itself.

Making the semantic data web easily writeable with RDFauthor

In this demo we present RDFauthor, an approach for authoring information that adheres to the RDF data model. RDFauthor completely hides syntax as well as RDF and ontology data model difficulties from end users and allows to edit information on arbitrary RDFa-annotated web pages. RDFauthor is based on extracting RDF triples from RDFa-annoted Web pages and transforming the RDFa-annotated HTML view into an editable form by using a set of authoring widgets. As a result, every RDFa-annotated web page can be made writeable, even if information originates from different sources.

Linked Data Kuratierung und Visualisierung mit semantischen Daten Wikis

Die visuelle Aufbereitung von Linked Data sowohl fur Zwecke der Prozessverarbeitung als auch zur Konsumierung durch Endanwender ist ein wichtiges Designelement in der unternehmerischen Aneignung von Semantic Web Technologien. Der Beitrag stellt aktuelle Ansatze in der Linked Data-Visualisierung vor, diskutiert deren Bedeutung im Enterprise Information Management und zeigt Beispiele, wie durch Best Practices unternehmerische Nutzungsszenarien von Linked Data unterstutzt werden konnen.